How about if this binary star system is orbiting another binary star system?
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A binary star system with Harden turned into a black hole.
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Due to movement, the binary star system wasn't observed by OGLE in 2005.
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This is possible in a binary star system, in which two stars orbit each other.
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This star was found as an almost invisible secondary star in a binary star system.
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Zellem later observed the first planet found to orbit a binary star system, Kepler-16b.
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It's one of two stars in a binary star system, partnered with a red dwarf star.
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And this binary-star system is one of the best characterized yet due to its eclipsing nature.
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TESS measurements of the binary star system helped astronomers discover the mutual eclipses and rule out pulsating.
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More realistically, 'Oumuamua was tossed from a hot, nascent binary star system still in its planet-making mode.
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In systems with multiple planets orbiting the same binary star system, "even wilder things can happen," he continued.
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The binary star system, where the stars are around a billion years old, is known as BD + 20 307.
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The exponent indicates the presence of a binary star system, so yes, this star has a companion named π2 Gruis.
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Scientists have never seen a binary star system in the midst of forming, but capture is given as one potential mechanism.
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Astronomers have now identified the source of that brief brightening — a binary star system a couple of thousand light-years away.
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That image was a mental stand-in for the prediction of planets orbiting a binary star system before the detection was made.
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The telescope high in the desert of Chile captured images of IRAS 16400-2422, a binary star system some 400 light years away.
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They studied the binary star system, HD101584, using the Atacama Large Millimeter/submillimeter Array of telescopes in Chile to find out what happened.
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While Breakthrough Starshot was initially packaged as a voyage to the nearby binary star system Alpha Centauri, the discovery of Proxima b changes everything.
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And when the first "Star Wars" film was made, astronomers had yet to discover a planet in the universe within a binary star system.
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A mere 8,000 light years away in our home galaxy is another black hole, this one part of a binary star system called V404 Cygni.
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One idea that they float is Mission Centaur, a small space telescope designed to locate any Earth-like planets discovered around the binary star system.
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After years of searching, their modern counterparts identified the source of that brief brightening — a binary star system a couple of thousand light-years away.
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Perhaps it came from a binary star system, or a system with a giant planet, either of which could have launched the object into interstellar space.
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It takes place once every 69 years in the binary star system TYC 6723-672-1 and lasts for approximately three and a half Earth-years.
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On March 6th, the European Southern Observatory (ESO) posted a mesmerizing image of a binary star system, captured by the agency's Atacama Large Millimeter/submillimeter Array (ALMA).
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"The orientation of this binary star system created a fantastic cosmic laboratory," said Scott Ransom, study co-author and an astronomer at the National Radio Astronomy Observatory.
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New research suggests this visitor from afar likely came from a binary star system, and that astronomers should be on the lookout for both interstellar asteroids and comets.
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This binary star system and its planets represents the smallest-separation twin binary, where both stars host planets, that has ever been observed, according to lead researcher Johanna Teske.
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That's all good—but scientists have come to the realization that a particular light source, one assumed to be binary star system in Andromeda, may actually be something far stranger.
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Most telescopes have a way of getting around the brightness of stars blocking the view of orbiting bodies, but most don't account for a binary star system like Alpha Centauri.
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In 2005, the Very Large Telescope was studying a potential exoplanet that happened to be in the same vicinity as V1213 Cen, a binary star system in the Centaurus constellation.
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And, at just 8,000 light years from the Earth in our own Milky Way galaxy, is a black hole that is part of a binary star system called V404 Cygni.
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The new image, released by the European Southern Observatory (ESO) on Wednesday, captures the aftermath of a confrontation inside a binary star system called HD101584, located thousands of light years from Earth.
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"This is the first evidence of frame-dragging in a binary star system," said lead author Vivek Venkatraman Krishnan, a physicist at the Max Planck Institute for Radio Astronomy, in an email.
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He was pointing out that the waves from a typical binary star system would carry away so little energy, we would never even notice that the system had changed—and that is true.
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The planets that researchers have turned up range from big and weird — like a Jupiter-sized planet orbiting a binary star system — to ones that are closer in size and orbit to Earth.
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Check out this mesmerizing animation of the binary star system AR Scorpii, in which a white dwarf repeatedly thrashes its red dwarf partner with jets of radiation, causing regular pulses every 1.97 minutes.
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Image: University of Warwick/Mark GarlickAstronomers using the ALMA telescope have discovered an oddly tilted planet-forming disk within a double binary star system, a configuration that up until this point only existed in theory.
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A planet orbiting a young binary star system might have been disturbed by another pair of stars that came too close about 2 million to 23 million years ago, soon after the planet was formed.
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One such idea began brewing in 2014, when de Mink and Ilya Mandel, an astrophysicist at the University of Birmingham and a member of the LIGO collaboration, realized that a type of binary-star system that de Mink has studied for years might be just the ticket to forming massive binary black holes.
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HD 165259 is visual binary star system in the southern constellation of Apus.
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HD 127726 is a binary star system in the northern constellation of Boötes.
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HD 216718 is a binary star system in the equatorial constellation of Aquarius.
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HD 174569 is a spectroscopic binary star system in the equatorial constellation of Aquila.
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HD 164509 is a binary star system composed of two main sequence stars in the constellation of Ophiuchus.
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Gamma Herculis, Latinized from γ Herculis, is a magnitude 3.74 binary star system in the northern constellation of Hercules.
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Recent measurements indicate that the binary star system has an age of several billion years -- comparable to the Solar System.
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Nu3 Canis Majoris, Latinized from ν3 Canis Majoris, is a binary star system in the southern constellation of Canis Major.
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Others are the result of mass transfer in a binary star system; examples of these include the barium stars and some S stars.
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LH54-425 is a spectroscopic binary star system in the LH 54 OB association within the Large Magellanic Cloud in the constellation Dorado.
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HD 200375 is a binary star system in the equatorial constellation of Aquarius. Their orbit does not yet have a unique solution available.
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Upsilon4 Eridani is a close binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.56. Based upon parallax measurements, the pair are located around from the Sun. This is a double-lined spectroscopic binary star system, which means that the Doppler-shifted spectral lines of both components can be distinguished.
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Mu Eridani (μ Eridani) is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 4.00. Based upon an annual parallax shift of 0.00625 arcseconds, it is located roughly 520 light years from the Sun. In 1910, this was determined to be a single-lined spectroscopic binary star system.
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The primary component of the binary star system, 2MASS J18082002−5104378 A, is a subgiant, cooler than the Sun, but larger and more luminous.
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HD 134064 is a binary star system in the northern constellation of Boötes. The pair are separated by a distance of around 8,000 AU.
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HD 31093 (also known as HIP 22573) is a binary star system in the constellation Caelum. HD 31093 is roughly 268 light years distant.
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Epsilon Ceti, Latinized from ε Ceti, is the Bayer designation for a binary star system located in the equatorial constellation of Cetus. It is faintly visible to the naked eye with an apparent visual magnitude of +4.84. Based upon an annual parallax shift of 14.58 mas, it is located around 98 light years away from the Sun. This is a line-width spectroscopic binary star system.
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Kruger 60 (DO Cephei) is a binary star system located 13.15 light-years from the Sun. These red dwarf stars orbit each other every 44.6 years.
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Kepler-432 is a binary star system with at least two planets in orbit around the primary companion, located about 2,830 light-years away from Earth.
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The two stars do not form a binary star system as 35 Leo is only 100 light years from Earth, thus separating the two stars by approximately .
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Pi4 Orionis (π4 Ori, π4 Orionis) is a binary star system in the western part of the Orion constellation. It is visible to the naked eye with an apparent visual magnitude of 3.7. Based upon an annual parallax shift of 3.1 mass, it is located roughly 1,050 light years from the Sun. This is a spectroscopic binary star system with an orbital period of 9.5 days and an eccentricity of 0.03.
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BB Doradus or BB Dor is a cataclysmic variable or nova-like star that is a binary star system composed of a red dwarf and a white dwarf.
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7 Vulpeculae is a binary star system approximately 940 light years away in the northern constellation of Vulpecula. It is a challenge to view with the naked eye, having an apparent visual magnitude of 6.33. The system is moving closer to the Earth with a heliocentric radial velocity of −38 km/s. This is a single-lined spectroscopic binary star system with an orbital period of 69.3 days and an eccentricity of 0.16.
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Tau8 Eridani, Latinized from τ8 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.65. The distance to this system can be estimated via the parallax method, yielding a value of around 380 light years. This is a single-lined spectroscopic binary star system with an orbital period of about 459 days and an eccentricity of 0.18.
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Most likely the pair form a binary star system. At least one of the stars appears to be a source of X-ray emission. The X-ray band flux is .
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This is a spectroscopic binary star system with a companion a mere 0.2 AU from the primary, assuming a distance of 71 parsecs, with an orbital period of 230 days.
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AG Draconis is a binary star system in the northern constellation of Draco. It consists of a giant star and a white dwarf that revolve around each other every 550 days.
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Kepler-296 is a binary star system in the constellation Draco. The primary star appears to be a late K-type main-sequence star, while the secondary is a red dwarf.
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Lambda Crateris, Latinized from λ Crateris, is the Bayer designation for a suspected binary star system in the southern constellation of Crater. With an annual parallax shift of 23.32 milliarcsecond as observed from Earth, it is located around 140 light years from the Sun. It is faintly visible to the naked eye with an apparent visual magnitude of 5.08. This is a probable astrometric binary star system, with orbital elements first reported by Abt and Levy (1976).
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Pi5 Orionis (π5 Ori, π5 Orionis) is a binary star system in the constellation Orion. It has an apparent visual magnitude of 3.69, which is bright enough to be visible to the naked eye on a clear night. Based upon an annual parallax shift of 2.43 mas, it is around 1,300 light years distant from the Sun. This is a single-lined spectroscopic binary star system in a circular orbit with an orbital period of 3.7005 days.
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Phi Herculis (φ Her) is a binary star system in the northern constellation of Hercules. Based upon an annual parallax shift of 15.99 mas as seen from Earth, it is located around 204 light years from the Sun. With a combined apparent visual magnitude of 4.24, it is bright enough to be seen with the naked eye. This is a single-lined spectroscopic binary star system with an orbital period of 564.8 days and an eccentricity of 0.526.
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Gamma Leonis (γ Leonis, abbreviated Gamma Leo, γ Leo), also named Algieba , is a binary star system in the constellation of Leo. In 2009, a planetary companion around the primary was announced.
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KELT-4 is a triple star system. KELT-4BC is a binary star system subcomponent of the triple, away from KELT-4A and the projected separation between KELT-4B and KELT-4C is .
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Epsilon Librae (ε Lib) is the Bayer designation for a binary star system in the zodiac constellation Libra. With an apparent visual magnitude of 4.922, it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 32.02 mas, it is located about 102 light years away from the Sun. This is a single-lined spectroscopic binary star system. The pair orbit each other with a period of 226.9 days and an eccentricity of 0.66.
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Kepler-14 is a binary star system targeted by the Kepler spacecraft. It is host to one known planet: the Jupiter-like Kepler-14b. The star system was identified by Kepler as a possible planetary host, but when imaging revealed that Kepler-14 was a binary star system and not a single star, the confirmation process became protracted. The stars are separated by at least 280 AU, and the stars complete an orbit around a common center of mass every 2800 years.
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The star KELT-2A is a late F-dwarf and is one member of the common-proper-motion binary star system KELT-2. KELT-2B is an early K-dwarf about 295 AU away.
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It is believed to be a binary star system. This star may be a member of the Scorpio- Centaurus OB association (Sco OB2). This is one of the nearest regions of recent star formation.
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Delta Aquilae (δ Aquilae, δ Aql) is a binary star system in the equatorial constellation of Aquila. It has an apparent visual magnitude of 3.4 and, based upon parallax measurements, is located about from Earth.
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TOI 1338 is a binary star system located in the constellation Pictor, about 1,320 light-years from Earth. It was discovered by TESS and is orbited by a circumbinary planet known as TOI 1338 b.
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HD 3322 is a binary star system in the northern constellation of Andromeda. With an apparent visual magnitude of 6.51, it lies below the nominal brightness limit for visibility with the normal naked eye, but it is still possible to see the star with excellent vision under ideal seeing conditions. An annual parallax shift of provides a distance estimate of roughly 700 light years. This is a single-lined spectroscopic binary star system with an orbital period of around 400 days and an eccentricity of 0.57.
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HD 214448 is a binary star system in the equatorial constellation of Aquarius. They orbit each other with a period of around 147 years. The combined mass of the pair is twice that of the Sun.
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There is a remote chance that the Earth will instead be captured by a passing binary star system, allowing the planet's biosphere to remain intact. The odds of this happening are about one chance in three million.
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This is a double-lined spectroscopic binary star system. The spectrum matches a B-type main-sequence star with a stellar classification of B2.5 V. There is a faint visual companion with an apparent magnitude of 12.49.
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Kappa Cancri, Latinized from κ Cancri, is a blue-white hued binary star system in the zodiac constellation of Cancer. It is faintly visible to the naked eye with an apparent visual magnitude of +5.23. The magnitude difference between the two stars is about 2.6. Based upon an annual parallax shift of 7.13 mas as seen from the Earth, the system is located roughly 460 light years from the Sun. This is a single-lined spectroscopic binary star system with an orbital period of 6.39 days and an eccentricity of 0.13.
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An eclipsing binary star is a binary star system in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses. In the case where the binary is also a spectroscopic binary and the parallax of the system is known, the binary is quite valuable for stellar analysis. Algol, a triple star system in the constellation Perseus, contains the best-known example of an eclipsing binary. This video shows an artist's impression of an eclipsing binary star system.
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70 Ophiuchi is a binary star system located 16.6 light years away from the Earth. It is in the constellation Ophiuchus. At magnitude 4 it appears as a dim star visible to the unaided eye away from city lights.
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It regards females as unimportant. Alpha Centauri is also the name of Alpha Centauri's native star system. The Alpha Centauri binary star system is second only to Proxima Centauri in proximity to the Solar System, home to the Earth.
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2MASS J19383260+4603591 (Also known as Kepler-451) is a binary star system with at least one known planet, Kepler-451b. The system comprises two stars, a subdwarf B-type star as well as a small red dwarf star.
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HD 169405, also known as HR 6894, is a suspected binary star system in the southern constellation of Telescopium, about a degree to the north of Zeta Telescopii. It is an orange K-type giant of spectral type K0.5III.
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Gamma Virginis (γ Virginis, abbreviated Gamma Vir, γ Vir), officially named Porrima , is a binary star system in the constellation of Virgo. It consists of two almost identical main sequence stars at a distance of about 38 light years.
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They then plot the Spacer worlds on the ship's map, which form a rough sphere and conclude that the location of Earth must be near to the center of the sphere. This area turns out to have a binary star system.
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The General Catalogue of Variable Stars describes it as R:/PN, meaning it is likely a close binary star system with reflection of starlight being the cause of variation, as well as being part of the nucleus of a planetary nebula.
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RV Corvi is an eclipsing binary star system in the constellation Corvus, ranging from apparent magnitude 8.6 to 9.16 over 18 hours. The system is composed of stars of spectral types F0 and G0, which orbit each other every 0.7473 days.
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HD 131473 is a binary star system in the northern constellation of Boötes. The primary is an F-type subgiant with a stellar classification of F4IV, while its companion is a G-type subgiant with a stellar classification of G1IV.
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R Canis Majoris is an eclipsing interacting binary star system in the constellation Canis Major. It varies from magnitude 5.7 to 6.34. The system is unusual in the low ratio between the main two components and shortness of the orbital period.
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36 Serpentis is a binary star system in the equatorial constellation of Serpens. It has the Bayer designation b Serpentis, while 36 Serpentis is the Flamsteed designation. The system is visible to the naked eye as a dim, white- hued point of light with a combined apparent visual magnitude of 5.09. It is located 162 light years away from the Sun based on parallax, and is moving closer with a radial velocity of −8 km/s. This is a spectroscopic binary star system with a long orbital period of 52.8 years and a high eccentricity of 0.83.
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Beta Trianguli (Beta Tri, β Trianguli, β Tri) is the Bayer designation for a binary star system in the constellation Triangulum, located about 127 light years from Earth. Although the apparent magnitude is only 3.0, it is the brightest star in the constellation Triangulum. This is a double-lined spectroscopic binary star system with an orbital period of 31.39 days and an eccentricity of 0.53. The members are separated by a distance of less than 5 AU. The primary component has a stellar classification of A5IV, indicating that it has evolved away from the main sequence and is now a subgiant star.
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Measurements of these variations can be used, for example, to determine the orbital period and the radii of the members of an eclipsing binary star system, the rotation period of a minor planet or a star, or the total energy output of supernovae.
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WR 25 (HD 93162) is a binary star system in the turbulent star forming region Carina Nebula, about 6,800 light-years from Earth. It contains a Wolf-Rayet star and a hot luminous companion, and is a member of the Trumpler 16 cluster.
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It has about the same mass as the Sun, but has expanded to 44.7 times the Sun's radius. The star is radiating 391 times the solar luminosity. It is 366 ± 8 light-years distant from the Sun. Zeta Crateris is a binary star system.
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The competing scenario, that the system was formed out of a binary star system consisting of two normal (main sequence) stars, is not ruled out but is disfavored as black holes formed in such a binary are more likely to have positively aligned spins.
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CD Crucis, also known as HD 311884, is an eclipsing binary star system in the constellation Crux. It is around 14,000 light years away near the faint open cluster Hogg 15. The binary contains a Wolf–Rayet star and is also known as WR 47.
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HD 205877 is a visual binary star system in the constellation Indus. It also a double lined spectroscopic binary. The components are very similar and both are located on the giant branch in the Hertzsprung–Russell diagram in agreement with the F7III spectral type.
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Some planets orbit one member of a binary star system,Schwarz, Richard. Binary Catalogue of Exoplanets. Universität Wien and several circumbinary planets have been discovered which orbit around both members of binary star. A few planets in triple star systems are knownSchwarz, Richard. STAR-DATA.
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HD 156411 is a star hotter and larger than the sun with a gas giant planet in orbit. Gliese 674 is a nearby red dwarf star with a planet. Gliese 676 is a binary star system composed of two red dwarves with four planets.
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Beta Crateris, Latinized from β Crateris, is a binary star system in the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.46. Based upon an annual parallax shift of 9.59 mas as seen from Earth, it is located around 340 light years from the Sun. This is an astrometric binary star system with an orbital period of 6.0 years and a projected separation of 8.3 AU. The orbit has an estimated semimajor axis of 9.3 AU. The primary, component A, is listed as an A-type giant star with a stellar classification of A2 III.
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The very active star-forming region around the Tarantula Nebula in the Large Magellanic Cloud, where VFTS 352 is located VFTS 352 is a contact binary star system away in the Tarantula Nebula, which is part of the Large Magellanic Cloud. It is the most massive and earliest spectral type overcontact system known. The discovery of this O-type binary star system made use of the European Southern Observatory's Very Large Telescope, and the description was published on 13 October 2015. VFTS 352 is composed of two very hot (40,000 °C), bright and massive stars of equal size that orbit each other in little more than a day.
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Chi2 Hydrae, Latinised from χ2 Hydrae, is a binary star system in the equatorial constellation of Hydra. Based upon an annual parallax shift of 4.6 mas as seen from Earth, it is located roughly 710 light years from the Sun. It is visible to the naked eye with a combined apparent visual magnitude of 5.71. This is a detached eclipsing binary star system with an orbital period of 2.27 days and an essentially circular orbit having a measured eccentricity of 0.00. The eclipse of the primary by the secondary component reduces the visual magnitude of the system by 0.29, while the eclipse of the secondary diminishes the magnitude by 0.27.
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Xi Boötis (ξ Boo, ξ Boötis) is a binary star system 22 light years away from Earth. It is the nearest visible star in the constellation Boötes. The brighter, primary component of the pair has a visual magnitude of 4.70, making it visible to the naked eye.
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A hypothetical rendition of the Blue Moon orbiting high above the plane of its parent gas giant planet. The second episode of the program focuses on a fictional moon called the Blue Moon, which orbits an enormous gas giant that is itself orbiting a binary star system.
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The projected separation of the two components is , or . Proper motion measurements for the two stars are almost identical making HD 91324 a likely binary star system. The photometry of 2MASS J10313234–5338010 is consistent with it being a red dwarf of spectral type M5 or M6.
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26 Aurigae is a binary star system in the northern constellation of Auriga. It is visible to the naked eye as a faint star with an apparent visual magnitude of 5.41. The distance to this system remains poorly constrained. The new Hipparcos reduction gives a parallax of .
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EE Pegasi is an eclipsing binary star system in the constellation Pegasus. The two main components are two main sequence stars of spectral types A3V and F5V, with a third, smaller, star that is an orange or red dwarf orbiting the main pair every four years.
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Kappa Scorpii, Latinized from κ Scorpii, is a binary star system in the southern constellation of Scorpius. With an apparent visual magnitude of 2.4, this star system is readily visible to the naked eye. Parallax measurements place it at an estimated distance of roughly from the Earth.
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Collisions occur with greater frequency in the dense core regions of globular clusters (cf. blue stragglers). A likely scenario is a collision with a binary star system, or between two binary systems containing white dwarfs. This collision can leave behind a close binary system of two white dwarfs.
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One of the nearest known black holes to our Solar System is in this constellation. The binary star system A0620-00 in the constellation of Monoceros is at a distance of about roughly 3,300 light- years (1,000 parsecs) away. The black hole is estimated to be 6.6 solar masses.
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VB 10 or Van Biesbroeck's star Charles Earle Funk (1936) What's the Name, Please?: A Guide to the Correct Pronunciation of Current Prominent Names, p.161 is a very small and very dim red dwarf located in the constellation Aquila. It is part of a binary star system.
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The magnitude 5.97 secondary, component B, is a single-lined spectroscopic binary star system with an orbital period of 17.4 days and an eccentricity of 0.21. The pair have an angular separation of . The visible component is a B-type main-sequence star with a class of B8 V.
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The planet orbits in a circumbinary (M-type) binary star system named OGLE-2007-BLG-349L. They orbit around each other roughly every 9 days. The stars have masses of 0.41 and 0.30 , respectively. The age of the system, radii and temperatures of the stars are not known.
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Sky over Paranal. γ Volantis is in the centre of the image, above (actually northeast of) the Large Magellanic Cloud. Gamma Volantis, Latinized from γ Volantis, is a wide binary star system in the southern constellation of Volans. Based upon parallax measurements, it is approximately 142 light years from Earth.
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Upsilon Sagittarii (Upsilon Sgr, υ Sagittarii, υ Sgr) is a spectroscopic binary star system in the constellation Sagittarius. Upsilon Sagittarii is the prototypical hydrogen-deficient binary (HdB), and one of only four such systems known. The unusual spectrum of hydrogen-deficient binaries has made stellar classification of Upsilon Sagittarii difficult.
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HD 114762 is a binary star system approximately away in the constellation Coma Berenices. It consists of a yellow-white F-type main-sequence star and a red or brown dwarf companion approximately distant. Both are low-metal subdwarfs. A telescope or strong binoculars are needed to view the primary.
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40 Arietis is a probable binary star system in the northern constellation of Aries. 40 Arietis is the Flamsteed designation. Their combined apparent magnitude is 5.82, putting the system near the limit of naked eye visibility. Based upon an annual parallax shift of just , it is away from the Sun.
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Epsilon Sagittarii (Latinised from ε Sagittarii, abbreviated Epsilon Sgr, ε Sgr), formally named Kaus Australis , is a binary star system in the southern zodiac constellation of Sagittarius. The apparent visual magnitude of +1.85 makes it the brightest object in Sagittarius. Based upon parallax measurements, this star is around from the Sun.
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88 Tauri B, 69.56 arcseconds away, is a seventh-magnitude star that is also a binary star system. It is another spectroscopic binary whose components (88 Tauri Ba and Bb) orbit each other every 3.69 years. The orbit of 88 Tauri B around 88 Tauri A likely takes about 70,000 years.
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Kepler-34 is an eclipsing binary star system in the constellation of Cygnus. Both stars have roughly the same mass as the Sun, therefore both are spectral class G. They are separated by 0.22 AU, and complete an eccentric (e=0.5) orbit around a common center of mass every 27 days.
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In 2017 KIC 9832227, a binary star system, was predicted to merge and produce a red nova by early 2022. In September 2018, a typo was discovered in data used for the initial prediction, and it was determined that the merger would likely not take place at the predicted time.
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VB 10 is the secondary star of a bound binary star system. The primary is called Gliese 752, and hence VB 10 is also referred to as Gliese 752 B. The primary star is much larger and brighter. The two stars are separated by about 74 arc seconds (~434 AU).
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The MgI line: a new probe of the atmospheres of evaporating exoplanets The water vapour was detected in planetary atmosphere in 2018. The star KELT-2A is a member of the common- proper-motion binary star system KELT-2 (HD 42176). KELT-2B is an early K dwarf approximately 295 astronomical units away.
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There is a nearby companion star of class A0 IV located at an angular separation of 0.1 arc seconds along a position angle of 179°, as of 2002. Schöller et al. (2010) consider this to be a visual companion, although Eggleton and Tokovinin (2008) listed the pair as a probable binary star system.
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V Puppis (V Pup) is a star system in the constellation Puppis. Its apparent magnitude is 4.41. There is a binary star system at the center with a B1 dwarf orbiting a B3 subgiant star. They have an orbital period of 1.45 days and a distance of only 15 solar radii apart.
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HD 21447 is a probable binary star system located in the constellation Camelopardalis. The star is also known as HR 1046. It can be viewed with the naked eye, having an apparent visual magnitude of 5.09. Based upon an annual parallax shift of , it is located some 199 light years from the Sun.
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57 Aquilae (abbreviated 57 Aql) is a double star in the constellation of Aquila. 57 Aquilae is its Flamsteed designation. The primary star has an apparent visual magnitude of 5.70, while the secondary is magnitude 6.48. The pair have an angular separation of 35.624 arcseconds and probably form a wide binary star system.
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Tau Boötis, Latinized from τ Boötis, is an F-type main-sequence star approximately 51 light-years away in the constellation of Boötes. It is a binary star system, with the secondary star being a red dwarf. As of 1999, an extrasolar planet has been confirmed to be orbiting the primary star.
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One of his publications was on the study of the binary star system Beta Lyrae, which was published in the American Philosophical Society. The publication provided solutions to old problems about the systems of closed binary stars. Later astronomer Helmut Abt in the United States would confirm that the work was correct.
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It is radiating 89 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,400 K. Kappa Leonis has a magnitude 10.4 companion at an angular separation of 2.1 arc seconds. The pair most likely form a binary star system. The companion is a suspected variable star.
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10 Ursae Majoris is a binary star system in the northern constellation of Lynx. It is visible to the naked eye as a faint star with a combined apparent visual magnitude of 3.960. This system is fairly close to the Sun, at away from Earth. It is the third-brightest object in Lynx.
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Alpha Piscium (α Piscium) is a binary star system in the equatorial constellation of Pisces. Based upon parallax measurements made by the Hipparcos spacecraft, it is located approximately 311 light-years from the Sun. The two components are designated Alpha Piscium A (officially named Alrescha, the traditional name of the system) and B.
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Luyten 726-8, also known as Gliese 65, is a binary star system that is one of Earth's nearest neighbors, at about 8.7 light years from Earth in the constellation Cetus. Luyten 726-8B is also known under the variable star designation UV Ceti, being the archetype for the class of flare stars.
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Artist's impression of a young binary star system at periastron Pulsed Accretion in astronomy is the periodic modulation in accretion rate of young stellar objects in binary systems, producing a periodic pulse in the observed infrared light curves of T Tauri stars. In double stars in young stellar objects, a protoplanetary disk is formed around each star, accreted from matter close to the star. In such a binary star system a strongly eccentric orbit produces strong gravitational forces on the circumstellar disks at periastron, and such disturbance can lead to a temporary increase in the accretion rate onto the star. This increased accretion rate leads to a change of intensity in the infrared, such intensity rising by up to tenfold in the protostar LRLL 54361.
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Iota Cassiopeiae is known to be a quintuple star system. The brightest star system, ι Cassiopeiae A, contains a white-colored A-type main-sequence star with a mean apparent magnitude of +4.61. The primary component is a tighter binary star system itself. The two stars themselves were resolved by adaptive optics, revealing two stars.
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According to Eggleton and Tokovinin (2008), this is a suspected binary star system with an orbital period of 4.9 days and an eccentricity of 0.2. However, De Rosa et al. (2014) did not find a companion. The primary is metallic-lined (Am) star, meaning it has unusually strong absorption lines of metals in its spectrum.
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9 Cygni is a binary star system in the northern constellation of Cygnus. 9 Cygni is its Flamsteed designation. The two stars have a combined magnitude of 5.39, so it can be seen with the naked eye under good viewing conditions. Parallax measurements made by Gaia put the star at a distance of around () away.
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4U 0614+091 is a low-mass X-ray binary star system which features a neutron star and a low-mass companion star. The binary system lies 10,000 light-years away in Orion. It produces jets like a microquasar, the first time an object other than a black hole has been shown to produce jets.
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HD 73390, also called e1 Carinae, is a binary star system in the constellation Carina. It is approximately 870 light years from Earth. The primary is a blue- white B-type main sequence dwarf with an apparent magnitude of +5.27. It displays an infrared excess and is a candidate host of an orbiting debris disk.
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This is a spectroscopic binary star system with an estimated period of 2,500 days. The primary component is a red giant star with a stellar classification of M1.5 III. The outer envelope of this evolved star has expanded to 35 times the size of the Sun. The star has the same mass as the Sun.
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Some Wolf–Rayet stars are surrounded by pinwheel nebulae. These nebulae are formed from the dust that is spewed out of a binary star system. The stellar winds of the two stars collide and form two dust lanes that spiral outward with the rotation of the system. An example of this is WR 104.
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Chini et al. (2012) identify this as a double-lined spectroscopic binary star system. It shows a stellar classification of O9.7 Iab, matching a massive O-type supergiant star. Along with the O-type star 16 Sgr (HD 167263), it is ionizing an H II region along the western edge of the molecular cloud L291.
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BG Geminorum is an eclipsing binary star system in the constellation Gemini. It consists of a K0 supergiant with a more massive but unseen companion. The companion is likely to be either a black hole or class B star. Material from the K0 star is being transferred to an accretion disk surrounding the unidentified object.
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Tau1 Eridani, Latinized from τ1 Eridani, is a binary star system in the constellation Eridanus. It has an apparent magnitude of 4.46, making it visible to the naked eye in suitably dark conditions. This a spectroscopic binary with an orbital period of 958 days. It is located about 46 light years from the Earth.
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Gliese 777, often abbreviated as Gl 777 or GJ 777, is a yellow subgiant approximately 52 light-years away in the constellation of Cygnus. The system is also a binary star system made up of two stars and possibly a third. As of 2005, two extrasolar planets are known to orbit the primary star.
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Tau5 Eridani, Latinized from τ5 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.26. The distance to this system, as estimated using the parallax technique, is around 293 light years. Tau5 Eridani is a double-lined spectroscopic binary system.
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Kepler-432 is a binary star system composed of a K-type giant star (Kepler-432 A) and a red dwarf star (Kepler-432 B). The apparent magnitude of the system, or how bright it appears from Earth's perspective, is about 15.8. Therefore, it is too dim to be seen with the naked eye.
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A symbiotic binary star is a variable binary star system in which a red giant has expanded its outer envelope and is shedding mass quickly, and another hot star (often a white dwarf) is ionizing the gas. Three symbiotic binaries as of 1999 are SSXSs: AG Dra (BB, MW), RR Tel (WD, MW), and RX J0048.4-7332 (WD, SMC).
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Delta Equulei, Latinized from δ Equulei, is the second brightest star in the constellation Equuleus. Delta Equulei is a binary star system about 60 light years away, with components of class G0 and F5. Their combined magnitude is 4.47, and their absolute magnitude is 3.142. There is controversy as to the exact masses of the stars.
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WR 22, also known as V429 Carinae or HR 4188, is an eclipsing binary star system in the constellation Carina. The system contains a Wolf-Rayet (WR) star that is one of the most massive and most luminous stars known, and is also a bright x-ray source due to colliding winds with a less massive O class companion.
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27 Piscium is a binary star system in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.88. Based upon an annual parallax shift of , it is located about 234 light years away. The system is positioned near the ecliptic and so is subject to occultation by the Moon.
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U Coronae Borealis (U CrB) is an Algol-type eclipsing binary star system in the constellation Corona Borealis. Its apparent magnitude varies between 7.66 and 8.79 over a period of 3.45 days The component stars are a blue-white main sequence star of spectral type B6V and a cooler yellow-white subgiant star of spectral type F8III-IV.
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Located near Eta Cygni is the X-ray source Cygnus X-1, which is now thought to be caused by a black hole accreting matter in a binary star system. This was the first x-ray source widely believed to be a black hole. The two component stars of Albireo are easily distinguished, even in a small telescope.
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30 Persei is a binary star system in the northern constellation Perseus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.49. Based upon an annual parallax shift of , is located roughly 730 light years from the Sun. It is a member of the Perseus OB3 association, which includes the Alpha Persei Cluster.
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14 Sagittae is a binary star system in the equatorial constellation of Aquila. 14 Sagittae is the Flamsteed designation. It appears as a sixth magnitude star, near the lower limit of visibility to the naked eye, having an apparent visual magnitude of 5.89. The system is located 660 light years away, as determined from its annual parallax shift of .
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ADS 7251 is a binary star system 6.16 ±0.02 parsecs (20.09 ±0.07 light years) from the Sun. Both are of nearly equal brightness, but ADS 7251 A, which is 0.06 magnitudes (1.2 times) brighter than ADS 7251 B, is a red dwarf of spectral type M0.0. The latter is spectral type K7.0 and slightly further away.
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HD 83446 is a probable astrometric binary star system in the constellation Vela. It is visible to the naked eye with an apparent visual magnitude of 4.34. Based upon an annual parallax shift of , it is located 107.1 light years from the Sun. The system is moving further away with a heliocentric radial velocity of +18 km/s.
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53 Aurigae is a binary star system in the northern constellation of Auriga. It is visible to the naked eye as a dim star with a combined apparent visual magnitude of 5.74. Parallax estimates put it at a distance of away. The system is receding from the Earth with a heliocentric radial velocity of 13 km/s.
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Rho Aurigae (ρ Aur, ρ Aurigae) is the Bayer designation for a binary star system in the northern constellation of Auriga. It is faintly visible to the naked eye with an apparent visual magnitude of +5.22. Judging by parallax measurements, this system is approximately distant from the Earth, give or take a 30 light-year margin of error.
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2 Andromedae, abbreviated 2 And, is a binary star system in the northern constellation of Andromeda. 2 Andromedae is the Flamsteed designation. It is a faint star system but visible to the naked eye with a combined apparent visual magnitude of 5.09. Based upon an annual parallax shift of , it is located 420 light years away.
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10 Arietis is a binary star system in the northern constellation of Aries. 10 Arietis is the Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with a combined apparent visual magnitude of 5.63. Based upon parallax measurements, it is located around 159 light years away from the Sun.
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64 Arietis is a possible binary star system in the northern constellation of Aries. 64 Arietis is the Flamsteed designation. It is faintly visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of +5.67. Based upon an annual parallax shift of , this star is approximately distant from the Sun.
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86 Aquarii (abbreviated 86 Aqr) is a binary star system in the equatorial constellation of Aquarius. 86 Aquarii is the Flamsteed designation, though it also bears the Bayer designation c1 Aquarii. It is faint but visible to the naked eye with an apparent visual magnitude of +4.47. Based upon parallax measurements, the distance to this star is about .
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10 Andromedae, abbreviated 10 And, is an astrometric binary star system in the northern constellation of Andromeda. 10 Andromedae is the Flamsteed designation. It has an apparent visual magnitude of approximately 5.81, which means it is faintly visible to the naked eye. Based upon an annual parallax shift of , it is located 492 light years away.
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59 Andromedae, abbreviated 59 And, is a sixth-magnitude binary star system in the northern constellation of Andromeda. 59 Andromedae is the Flamsteed designation. As of 2017, the pair had an angular separation of along a position angle (PA) of 36°. Compare this to a separation of along a PA of 35°, as measured in 1783.
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Kepler-47c (also known as Kepler-47(AB)-c and by its Kepler Object of Interest designation KOI-3154.02) is an exoplanet orbiting the binary star system Kepler-47, the outermost of three such planets discovered by NASA's Kepler spacecraft. The system, also involving two other exoplanets, is located about 3,400 light-years (1,060 parsecs) away.
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WD J0651+2844 is a white dwarf binary star system composed of two white dwarfs. They are approximately 120,000 km apart and complete an orbit around their barycenter in less than 13 minutes. This produces an eclipse every 6 minutes. This makes it possible to gather enough data to produce extremely accurate predictions of each future eclipse.
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41 Capricorni is a binary star system in the southern constellation of Capricornus. It is faintly visible to the naked eye with an apparent visual magnitude of +5.24. The distance to this star, based upon an annual parallax shift of , is around 171 light years. It is moving closer with a heliocentric radial velocity of −45 km/s.
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Kepler-47b (also known as Kepler-47 (AB) b and by its Kepler Object of Interest designation KOI-3154.01) is an exoplanet orbiting the binary star system Kepler-47, the innermost of three such planets discovered by NASA's Kepler spacecraft. The system, also involving two other exoplanets, is located about 3,400 light-years (1,060 parsecs) away.
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Hen 2-428 is a planetary nebula with a binary double white dwarf system core. This core star system is the first discovered candidate for Type Ia supernova through binary white dwarf merger process. At the time of its discovery, the star system at the core was the heaviest known double white dwarf binary star system.
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Kepler-35 is a binary star system in the constellation of Cygnus. These stars, called Kepler-35A and Kepler-35B have masses of 89% and 81% solar masses respectively, and both are assumed to be of spectral class G. They are separated by 0.176 AU, and complete an eccentric orbit around a common center of mass every 20.73 days.
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Furuhjelm 46, also known as HD 155876 and Gliese 661, is a nearby binary star system, consisting of two very similar red dwarfs, located in the constellation Hercules. Furuhjelm 46 is the nearest "true" (i. e. not brown dwarf) star system in Hercules, however, there is brown dwarf in this constellation, located closer: WISE 1741+2553.
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Her X-1 is the prototype for the massive X-ray binaries although it falls on the borderline, , between high- and low-mass X-ray binaries. An intermediate-mass X-ray binary (IMXB) is a binary star system where one of the components is a neutron star or a black hole. The other component is an intermediate mass star.
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15 Sagittarii is a blue-hued binary star system in the southern zodiac constellation of Sagittarius. The estimated distance based upon photometry is around . It is faintly visible to the naked eye with an apparent visual magnitude of 5.37. The system is moving closer to the Sun with a heliocentric radial velocity of around −6 km/s.
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HD 213240 is a possible binary star system in the constellation Grus. It has an apparent visual magnitude of 6.81, which lies below the limit of visibility for normal human sight. The system is located at a distance of 133.5 light years from the Sun based on parallax. The primary has an absolute magnitude of 3.77.
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6 Persei is a binary star system in the northern constellation of Andromeda. It is faintly visible to the naked eye with an apparent visual magnitude of 5.29. The system is located 182 light years from Earth, as determined from its annual parallax shift of . It is moving further away with a heliocentric radial velocity of +42 km/s.
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WASP-2 is a binary star system in the Delphinus constellation located about 500 light-years away. The primary is magnitude 12 orange dwarf star, orbited by red dwarf star on wide orbit.Precise Differential Analysis of Stellar Metallicities: Application to Solar Analogs Including 16 Cyg A and B The star system shows an infrared excess noise of unknown origin.
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KT Lupi is a visual binary star system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.55. As of 1983, the pair had an angular separation of . Based upon an annual parallax shift of as seen from Earth's orbit, it is located 430 light years from the Sun.
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2 Lyncis is a binary star system in the northern constellation Lynx. It is visible to the naked eye, having an apparent visual magnitude of 4.44. The distance to this system, judging by an annual parallax shift of , is around 157 light years. It is moving closer to the Sun with a heliocentric radial velocity of −2 km/s.
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Gamma Delphini, Latinized from γ Delphini, is a binary star system approximately 101 light-years away in the constellation of Delphinus. The star marks one corner of the asterism "Job's Coffin". It is one of the best known double stars in the sky, consisting of a fourth magnitude orange subgiant and a fifth magnitude yellow-white dwarf.
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HD 125628 is a binary star system in the constellation Centaurus. It is faintly visible to the naked eye with a combined apparent visual magnitude of 4.76. The distance to this system is approximately 380 light years based on parallax. It is drifting further away from the Sun with a radial velocity of +15 km/s.
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HD 126128/9 is a triple star in the northern constellation of Boötes. Two of the components (HD 126128) form a binary star system with an orbital period of 39.5 years and an eccentricity of 0.25. The third component (HD 126129), and the brightest member of the trio, lies at an angular separation of 6.250″ from the other two.
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In 1989 (and 1999 ) this scenario was extended to binary neutron star mergers (a binary star system of two neutron stars that collide). After preliminary identification of these sites, the scenario was confirmed in GW170817. Current astrophysical models suggest that a single neutron star merger event may have generated between 3 and 13 Earth masses of gold.
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Zeta Crucis, Latinized from ζ Crucis, is a binary star system in the southern constellation of Crux. It is visible to the naked eye with an apparent magnitude of 4.06m. ζ Crucis is located at about 360 light-years from the Sun. It is a member of the Lower Centaurus Crux subgroup of the Scorpius-Centaurus Association.
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Eta Sagittarii (Eta Sgr, η Sagittarii, η Sgr) is a binary star system in the southern zodiac constellation of Sagittarius. Based upon parallax measurements, it is located at a distance of from Earth. It was formerly known as Beta Telescopii (β Tel). In India, where part of the constellation of Sagittarius represents an Elephant, this star forms the creature's tail.
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Zeta Volantis (ζ Vol, ζ Volantis) is a binary star system in the southern constellation of Volans. It has an apparent visual magnitude of 3.93, which is bright enough to be seen with the naked eye. Based upon parallax measurements, it is approximately 141 light years from the Sun. The companion is a magnitude 9.7 star at an angular separation of 16.7″.
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DS Tucanae (HD 222259) is a binary star system in the constellation of Tucana. It has an apparent visual magnitude of 8.5, and is a RS Canum Venaticorum variable. The system is notable for being young as a member of the 45 Myr old Tucana-Horologium moving group and for the primary star hosting the confirmed exoplanet DS Tucanae Ab, discovered by TESS.
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12 Persei (12 Per) is a double-lined spectroscopic binary star system in the northern constellation Perseus. Its combined apparent magnitude is 4.94, which means it can be viewed with the naked eye. Based upon parallax measurements, this system is about 79 light years away from the Sun. The magnitude difference between the two components is estimated to be 0.51.
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33 Piscium is a binary star system in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.61. The distance to this system, as determined from an annual parallax shift of , is about 129 light years. It is moving closer to the Sun with a heliocentric radial velocity of −6.6 km/s.
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Schematic of a binary star system with one planet on an S-type orbit and one on a P-type orbit. Planets in binary star systems may be candidates for supporting extraterrestrial life. Habitability of binary star systems is determined by many factors from a variety of sources. Typical estimates often suggest that 50% or more of all star systems are binary systems.
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Gliese 673 is an orange dwarf star in the constellation Ophiuchus. It has a stellar classification of K7V. Main sequence stars with this spectra have a mass in the range of 60-70% of solar mass () (comparable to the members of the binary star system 61 Cygni). This star is relatively near our Sun at a distance of about 25 light years.
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DV Aquarii is a binary star system in the zodiac constellation of Aquarius. It has a peak apparent visual magnitude of 5.89, which is bright enough to be visible to the naked eye. The distance can be estimated from its annual parallax shift of , yielding a separation of 291 light years. This is a detached eclipsing binary system of the Beta Lyrae type.
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HD 115404 is a binary star system located in the constellation Coma Berenices. Parallax measurements made by Hipparcos put the system at 36 light-years, or 11 parsecs, away. The combined apparent magnitude of the system is 6.52, with the magnitudes of the components being 6.66 and 9.50. The primary component, designated A, is a K-type main sequence star.
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AT Microscopii is a binary star system located at a distance of from the Sun in the constellation of Microscopium. Both members are flare stars, meaning they are red dwarf stars that undergo random eruptions that increase their brightness. This pair lies physically near the red dwarf star AU Microscopii, which may mean they form a wide triple star system.
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Omicron Puppis (ο Puppis) is candidate binary star system in the southern constellation of Puppis. It is visible to the naked eye, having a combined apparent visual magnitude of +4.48. Based upon an annual parallax shift of 2.30 mas as seen from Earth, it is located roughly 1,400 light years from the Sun. This is a suspected close spectroscopic binary system.
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Finally, the 'p' shows some peculiarity in the spectrum. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +5.43 to +5.61. This is a runaway star with a peculiar velocity of . Because it is a binary star system, it was most likely not turned into a runaway system as the result of a supernova explosion.
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HD 199942 is a binary star system in the northern constellation of Equuleus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.98. The system is located at a distance of approximately 184 light years based on parallax, and it has an absolute magnitude of 1.59. It is drifting closer with a radial velocity of −26 km/s.
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HD 91324 is a likely binary star system in the southern constellation of Vela. It is visible to the naked eye with an apparent visual magnitude of 4.89. The distance to HD 91324, as determined from its annual parallax shift of , is 71.5 light years. It is moving further from the Earth with a heliocentric radial velocity of +21 km/s.
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HR 4180 is a double star with components HD 92449 and HD 92463 in the southern constellation of Vela. They are probably members of a binary star system. HR 4180 can be viewed with the naked eye, having an apparent visual magnitude of 4.29. Based upon an annual parallax shift of , it is located 640 light years from the Sun.
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132 Tauri is a binary star system in the constellation Taurus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.89. Based upon a poorly-constrained annual parallax shift of , it is located roughly 360 light years from the Sun. The system is moving further away with a heliocentric radial velocity of +16 km/s.
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27 Arietis is a binary star system in the northern constellation of Aries. 27 Arietis is the Flamsteed designation. It is a dim, yellow-hued star that is close to the lower limit of what can be viewed with the naked eye, having an apparent visual magnitude is 6.21. The annual parallax shift of corresponds to a physical distance of approximately from Earth.
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T Pyxidis (T Pyx)According to the Argelander system of nomenclature for variable stars, the initial letter is an R, and the counter progresses alphabetically. Thus, T Pyx is the third variable star in the constellation Pyx. is a recurrent nova and nova remnant in the constellation Pyxis. It is a binary star system and its distance is estimated at about from Earth.
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21 Arietis (abbreviated 21 Ari) is a binary star system in the northern constellation of Aries. 21 Arietis is the Flamsteed designation. It has a combined apparent visual magnitude is 5.57; the brighter member is magnitude 6.40 while the fainter star is magnitude 6.48. The distance to this star system, based upon an annual parallax shift of 19.58 mas, is .
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97 Aquarii (abbreviated 97 Aqr) is a binary star system in the equatorial constellation of Aquarius. 97 Aquarii is the Flamsteed designation. The combined apparent visual magnitude of the system is 5.20; the brighter star is magnitude 5.59 while the companion is magnitude 6.72. Based upon an annual parallax shift of 15.30 milliarcseconds, this system is at a distance of around from Earth.
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36 Andromedae is a visual binary star system in the northern constellation of Andromeda. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. It is faintly visible to the naked eye with an apparent visual magnitude of 5.45. An annual parallax shift of 26.33 mas yields a distance estimate of about 124 light years.
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C3 Centauri is a suspected astrometric binary star system in the southern constellation of Centaurus. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.46. The distance to this object is approximately 342 light years based on parallax. It is a member of the Hyades Stream of co-moving stars.
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Spectrographic images taken at the Cape Observatory between 1921 and 1923 showed this star has a variable radial velocity, which indicated this is a single-lined spectroscopic binary star system. The pair have an orbital period of 9.94 days and an eccentricity of about 0.2. The primary component has received a number of different stellar classifications. For example, Jaschek et al.
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31 Crateris is a binary star system in the constellation Corvus. Varying between apparent magnitudes 5.19 and 5.23 over 1.48 days, it has the variable star designation of TY Corvi. It is actually a remote system with a hot blue- white star of spectral type B1.5V and a companion about which little is known. The two stars orbit each other every 2.9631 days.
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Gliese 752 is a binary star system in the Aquila constellation. This system is relatively nearby, at a distance of about 19 light years. This system consists of two M-type stars. The primary star is the magnitude 9 Gliese (GJ) 752 A. The secondary star is the dim magnitude 17 Gliese (GJ) 752 B, more commonly referred to as VB 10.
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Alcor is a binary star system in the constellation of Ursa Major. It is the fainter companion of Mizar, the two stars forming a naked eye double in the handle of the Big Dipper (or Plough) asterism in the constellation of Ursa Major. The two both lie about 83 light-years away from the Sun, as measured by the Hipparcos astrometry satellite.
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HD 29573 is a binary star system in the constellation Eridanus. It has a combined apparent visual magnitude of 4.99, making it visible to the naked eye. Based upon an annual parallax shift of , it is located 217 light years from the Sun. The system is moving further away from Earth with a heliocentric radial velocity of +3 km/s.
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AU Microscopii is a member of the β Pictoris moving group. AU Microscopii may be gravitationally bound to the binary star system AT Microscopii. AU Microscopii has been observed in every part of the electromagnetic spectrum from radio to X-ray and is known to undergo flaring activity at all these wavelengths. Its flaring behaviour was first identified in 1973.
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T Cygni is a binary star system in the northern constellation of Cygnus. It is a faint system but visible to the naked eye with a combined apparent visual magnitude of 4.93. Based upon an annual Parallax shift of , it is located 387 light years away. It is moving closer to the Earth with a heliocentric radial velocity of −24 km/s.
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22 Cygni is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.95. The annual shift of yields a distance estimate of around 1,070 light years. It is moving closer to the Earth with a heliocentric radial velocity of −15 km/s.
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It has a projected rotational velocity of 255 km/s, resulting in an equatorial bulge with a radius 13% larger than the polar radius. It has a magnitude 9.5 companion G-type main sequence star that may form a binary star system with Delta Arae. There is a 12th magnitude optical companion located 47.4 arcseconds away along a position angle of 313°.
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HD 176051 is a spectroscopic binary star system approximately 49 light years away from Earth in the constellation Lyra. The pair orbit with a period of 22,423 days (61.4 years) and an eccentricity of 0.25. Compared to the Sun, they have a somewhat lower proportion of elements more massive than helium. Their individual masses are estimated at 1.07 and 0.71 solar masses ().
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42 Capricorni is a binary star system in the zodiac constellation of Capricornus. It has a combined apparent visual magnitude of 5.18, indicating it is faintly visible to the naked eye. An annual parallax shift of 30.09 mas yields a distance estimate of about 108 light years. The system is moving closer to the Sun with a radial velocity of −1.2 km/s.
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This star has 55% more mass than the Sun. It shines with 6.6 times the Sun's luminosity at an effective temperature of 7,132 K. This heat gives it the yellow-white glow of an F-type star. It has a faint companion located 31 arcseconds away with an apparent magnitude of +11.3. Most likely this pair form a binary star system.
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HD 30453 is a binary star system in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of 5.86. The system is located at a distance of approximately 334 light years from the Sun based on parallax. It is drifting further away from the Sun with a radial velocity of 16.65 km/s.
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Pi Aquarii, Latinized from π Aquarii, is the Bayer designation for a binary star in the equatorial constellation of Aquarius. This system has an apparent visual magnitude of a mean apparent magnitude of +4.57. Based upon parallax measurements, it is located at a distance of roughly from Earth. This is a binary star system with an orbital period of 84.1 days.
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Gliese 412 is a pair of stars that share a common proper motion through space and are thought to form a binary star system. The pair have an angular separation of 31.4″ at a position angle of 126.1°. They are located 15.8 light years distant from the Sun in the constellation Ursa Major. Both components are relatively dim red dwarf stars.
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HD 3346, also known as V428 Andromedae, is a binary star system in the northern constellation of Andromeda. It is a dim star but visible to the naked eye under suitable viewing conditions, having an apparent visual magnitude of 5.14. The distance to HD 3346 can be determined from its annual parallax shift of . This yields a range of about 660 light year.
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U Geminorum (U Gem), in the constellation Gemini, is an archetypal example of a dwarf nova. The binary star system consists of a white dwarf closely orbiting a red dwarf. Every few months it undergoes an outburst that greatly increases its brightness. The dwarf nova class of variable stars are often referred to as U Geminorum variables after this star.
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HR 7484 (V1143 Cyg) is a binary star system in the northern constellation of Cygnus. It is dimly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 5.89. Based upon an annual parallax shift of 24.71, it is located 132 light years away. The system is moving closer with a heliocentric radial velocity of −14 km/s.
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HD 195019 b is an exoplanet orbiting around HD 195019 in the binary star system. It has a minimum mass of 3.7 MJ. It orbits very close to the star. Like many planets at close distance, its orbit is circular, even more circular or less eccentric than Earth. It takes 437 hours to orbit with velocity of 83.24 kilometers per second.
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It is in reality a remote binary star system with a hot blue-white star of spectral type B1.5V and a companion about which little is known. The two stars orbit each other every 2.9631 days. The primary is possibly a blue straggler of the Hyades group. The primary is around 15.5 times as massive as the Sun and 52262 times as luminous.
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Consider a binary star system. This consists of two objects, of mass m_1 and m_2, orbiting around their centre of mass. m_1 has position vector r_1 and orbital velocity v_1, and m_2 has position vector r_2 and orbital velocity v_2 relative to the centre of mass. The separation between the two stars is denoted r, and is assumed to be constant.
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12 Nevertheless, objects as small as 8 Jupiter masses have been called a brown dwarf.Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk, Luhman, et al., 2005 A substellar companion is thought to exist in the binary star system SDSS 1212.Detection of Substellar Companion in Interacting Binary Substellar companions have been confirmed by analyzing astrometric data from Hipparcos.
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HD 151613 is a binary star system in the northern circumpolar constellation of Draco. It is visible to the naked eye with an apparent visual magnitude of 4.84. The distance to this star, as estimated from its annual parallax shift of , is 83 light years. It is moving closer to the Earth with a heliocentric radial velocity of −2 km/s.
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HD 217382 is a suspected binary star system in the northern circumpolar constellation of Cepheus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.70. The distance to HD 217382 is around 319 light years, as determined from an annual parallax shift of . The system is moving further away with a heliocentric radial velocity of +2.6 km/s.
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Delta Trianguli (Delta Tri, δ Trianguli, δ Tri) is a spectroscopic binary star system approximately away in the constellation of Triangulum. The primary star is a yellow dwarf, while the secondary star is thought to be an orange dwarf. It has an apparent magnitude of +4.87 and forms an optical (line-of-sight) triple with Gamma Trianguli and 7 Trianguli.
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Observational studies of their radial velocity suggested that all barium stars are binary stars. Observations in the ultraviolet using International Ultraviolet Explorer detected white dwarfs in some barium star systems. Barium stars are believed to be the result of mass transfer in a binary star system. The mass transfer occurred when the now-observed giant star was on the main sequence.
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X Caeli, or Gamma2 Caeli, is a binary star system in the southern constellation of Caelum. It is barely visible to the naked eye with an apparent visual magnitude of 6.32. based upon an annual parallax shift of , it is located 341 light years from Earth. The system is moving further away with a heliocentric radial velocity of +6 km/s.
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HD 42818 is a suspected astrometric binary star system in the northern circumpolar constellation of Camelopardalis. It is visible to the naked eye with an apparent visual magnitude of +4.76. Based upon an annual parallax shift of as seen from Earth's orbit, it is located some 175 light years away. The system appears to be moving closer with a heliocentric radial velocity of .
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KPD 1930+2752 is a binary star system including a Subdwarf B star and a probable white dwarf with relatively high mass. Due to the nature of this astronomical system, it seems like a likely candidate for a potential type Ia supernova, a type of supernova which occurs when a white dwarf star takes on enough matter to approach the Chandrasekhar limit, the point at which electron degeneracy pressure would not be enough to support its mass. However, carbon fusion would occur before this limit was reached, releasing enough energy to overcome the force of gravity holding the star together and resulting in a supernova. The total mass of the binary star system likely exceeds the Chandrasekhar limit, making this system one of the most likely candidates known to serve as a progenitor for a future type Ia supernova.
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21 Sagittarii is a binary star system in the southern zodiac constellation of Sagittarius. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.81. The system is located approximately 410 light years away from the Sun based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −11.80 km/s.
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HD 256 is a binary star system in the equatorial constellation of Cetus. It has a white hue and is dimly visible to the naked eye with an apparent visual magnitude of 6.20. Based upon parallax measurements, the system is located at a distance of approximately 474 light years from the Sun. It is drifting closer with a radial velocity of −10 km/s.
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Lambda Virginis (λ Virginis, abbreviated Lambda Vir, λ Vir) is a binary star system in the zodiac constellation of Virgo. With an apparent visual magnitude of 4.5, it is bright enough to be seen with the naked eye. Based upon parallax measurements, the system is about 173 light-years away from the Sun. Its two components are designated Lambda Virginis A (formally named Khambalia ) and B.
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Kappa2 Sagittarii (κ2 Sagittarii) is a binary star system in the zodiac constellation of Sagittarius. It is visible to the naked eye with a combined apparent visual magnitude of +5.64. Based upon an annual parallax shift of 10.47 mas as seen from Earth, this system is located around 310 light years from the Sun. They are receding with a radial velocity of +2.6 km/s.
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6 Serpentis is a binary star system in the constellation Serpens. It has a combined apparent visual magnitude of 5.382, which is bright enough to be faintly visible to the naked eye. The distance to this system, based upon an annual parallax shift of , is about 240 light years. It is moving further from the Sun with a heliocentric radial velocity of +10 km/s.
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56 Pegasi is a binary star system in the northern constellation of Pegasus. It is visible to the naked eye with a combined apparent visual magnitude of 4.74. The system is approximately 590 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −28 km/s. It is listed as a member of the Wolf 630 moving group.
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Eta Cassiopeiae (η Cassiopeiae, abbreviated Eta Cas, η Cas) is a binary star system in the northern circumpolar constellation of Cassiopeia. Its binary nature was first discovered by William Herschel in August 1779. Based upon parallax measurements, the distance to this system is from the Sun. The two components are designated Eta Cassiopeiae A (officially named Achird , the traditional name for the system) and B.
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Nu Orionis (ν Orionis) is a binary star system in the northeastern part of the constellation Orion. It should not be confused with the variable star NU Orionis. Nu Orionis has an apparent visual magnitude of 4.42, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 0.00632 arcseconds, the distance to this system is roughly 520 light years.
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4 Ursae Minoris is a binary star system in the northern circumpolar constellation Ursa Minor. It is faintly visible to the naked eye with an apparent visual magnitude of 4.80. Based upon an annual parallax shift of as seen from Earth's orbit, it is located roughly 460 light years from the Sun. It is moving further away with a heliocentric radial velocity of +5.9 km/s.
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83 Leonis, abbreviated 83 Leo, is a binary star system approximately 59 light- years away in the constellation of Leo (the Lion). The primary star of the system is a cool orange subgiant star, while the secondary star is an orange dwarf star. The two stars are separated by at least 515 astronomical units from each other. Both stars are presumed to be cooler than the Sun.
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ADS 16402 is a binary star system in Lacerta, around which a planet orbits with some unusual properties.Puzzling Puffy Planet, Less Dense Than Cork, Is Discovered - New York Times The Jupiter-sized planet exhibits an unexpectedly low density, about the same as cork. This planet is dubbed HAT P-1. EV Lacertae is a rapidly spinning magnitude 10 red dwarf with a strong magnetic field.
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This is a single-lined spectroscopic binary star system that belongs to the Pleiades stream. As of 2011, the pair had a linear projected separation of . The primary component is a mercury-manganese star with a stellar classification of B8II/III. These stars are often helium- weak, but this is one of the most normal members of this group in terms of helium abundance.
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The light curve of an intermediate polar may show several types of stable periodic changes in brightness. One periodicity is related to the orbital period of the binary star system. The orbital periods of confirmed intermediate polars range from 1.4 to 48 hours, with typical values between 3 and 6 hours. A second periodic signal originates from the rotation of the white dwarf spinning on its axis.
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Sigma Ceti (σ Ceti) is the Bayer designation for a star in the equatorial constellation of Cetus. With an apparent visual magnitude of 4.78, it can be seen with the naked eye on a dark night. Based upon an annual parallax shift of 37.46 mas, it lies at an estimated distance of 87.1 light years from the Sun. It is a probable astrometric binary star system.
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57 Cygni is a close binary star system in the constellation Cygnus, located about 530 light years from Earth. It is visible to the naked eye as a blue- white hued star with a baseline apparent visual magnitude of 4.80. The pair have a magnitude difference of 0.34. This system is moving closer to the Earth with a heliocentric radial velocity of −21 km/s.
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HD 85622 is a binary star system in the southern constellation of Vela. It is visible to the naked eye with an apparent visual magnitude of 4.58. The distance to HD 85622 can be estimated from its annual parallax shift of , yielding a value of 750 light years. It is moving further from the Earth with a heliocentric radial velocity of +8 km/s.
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4 Cygni is a binary star system in the northern constellation of Cygnus. It is a faintly visible to the naked eye with an apparent visual magnitude of 5.17. The distance to 4 Cygni, as determined from its annual parallax shift of , is about 560 light years. This is single-lined spectroscopic binary with an orbital period of 35 days and an eccentricity of 0.45.
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Omicron Aurigae, Latinized from ο Aurigae, is the Bayer designation for an astrometric binary star system in the northern constellation of Auriga. With an apparent visual magnitude of 5.47, it is faintly visible to the naked eye. Based upon an annual parallax shift of , it is approximately distant from Earth. The star is a member of the Ursa Major stream of co-moving stars.
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17 Aquarii, abbreviated 17 Aqr, is a spectroscopic binary star system in the constellation of Aquarius. 17 Aquarii is the Flamsteed designation. It appears to the naked eye as a faint sixth magnitude star, having a combined apparent visual magnitude of 5.99. The distance to 17 Aqr can be estimated from its annual parallax shift of , which yields a separation of around 660 light years.
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26 Aquilae (abbreviated 26 Aql) is a binary star system in the equatorial constellation of Aquila. 20 Aquilae is its Flamsteed designation though it also bears the Bayer designation f Aquilae. It has an apparent visual magnitude of 5.00, which means it is faintly visible to the naked eye. As the Earth orbits the Sun, this star system undergoes a parallax shift of 21.15 mas.
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51 Aquarii is a binary star system located around 410 light years away from the Sun in the equatorial constellation of Aquarius. 51 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with a combined apparent visual magnitude of 5.78. The system is moving further from the Earth with a heliocentric radial velocity of +6 km/s.
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7 Aquarii, abbreviated 7 Aqr, is a binary star system in the zodiac constellation of Aquarius. 7 Aquarii is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 5.5; the brighter component is baseline magnitude 5.62 while the faint secondary is magnitude 11.4. As of 2002, the pair had an angular separation of along a position angle of 165°.
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26 Andromedae, abbreviated 26 And, is an astrometric binary star system in the constellation Andromeda. 26 Andromedae is the Flamsteed designation. It has a combined apparent visual magnitude of 6.10, which is near the lower limit of visibility to the naked eye. The distance to this system can be estimated from its annual parallax shift of , which yields a range of 610 light years.
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Xi Cancri (ξ Cancri, abbreviated Xi Cnc, ξ Cnc) is a spectroscopic binary star system in the zodiac constellation of Cancer. It is visible to the naked eye with an apparent visual magnitude of +5.15. Based upon parallax measurements obtained during the Hipparcos mission, it is roughly 370 light-years distant from the Sun. The two components are designated Xi Cancri A (formally named Nahn ) and B.
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Burnham disagrees, and dons a space suit to investigate in spite of the dangerous radiation from a nearby binary star system. She finds the object to be covered in ancient carvings, and guarded by an armed Klingon. The Klingon attacks, and when she uses her suit to escape she accidentally kills him. Burnham later awakens aboard the Shenzhou being treated for acute radiation sickness.
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Delta3 Tauri (δ3 Tauri) is a binary star system in the zodiac constellation of Taurus. Based upon an annual parallax shift of 21.96 mas as seen from Earth, it is located roughly 149 light years distant from the Sun. It is visible to the naked eye with a combined apparent visual magnitude of +4.32. δ3 Tauri is separated from δ1 Tauri by 0.72° on the sky.
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This star system was catalogued in the 1862 Bonner Durchmusterung ("Bonn astrometric Survey") as BD +18°4794B. It later appeared in Pickering's 1908 Harvard Revised Photometry Catalogue as HR 8210. The designation "IK Pegasi" follows the expanded form of the variable star nomenclature introduced by Friedrich W. Argelander. Examination of the spectrographic features of this star showed the characteristic absorption line shift of a binary star system.
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15 Eridani is a binary star system in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.875. Based upon parallax measurements, the system is located around 260 light years away from the Sun. It is moving further from the Earth with a heliocentric radial velocity of 24 km/s.
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38 Geminorum is a binary star system in the northern zodiac constellation of Gemini. It has the Bayer designation e Geminorum, while 38 Geminorum is the Flamsteed designation. This system is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.71. The primary component is a magnitude 4.75 star, while the secondary is magnitude 7.80.
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HAT-P-1b is an extrasolar planet orbiting the Sun-like star HAT-P-1, also known as ADS 16402 B. HAT-P-1 is the dimmer component of the ADS 16402 binary star system. It is located roughly 521 light years away from Earth in the constellation Lacerta. HAT-P-1b is among the least dense of any of the known extrasolar planets.
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HR 5110, also known as BH Canum Venaticorum, is a binary star system in the northern constellation of Canes Venatici. It is visible to the naked eye with an apparent visual magnitude of 4.91. Based upon an annual parallax shift of , it is located 149 light years away. The system is moving further from the Sun with a heliocentric radial velocity of 6.4 km/s.
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89 Herculis is a binary star system located about 4,700 light years away from the Sun in the northern constellation of Hercules. It is visible to the naked eye as a faint, fifth magnitude star. The system is moving closer to the Earth with a heliocentric radial velocity of −28.5 km/s. This is a spectroscopic binary with the pair surrounded by a dusty disc.
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Omega Andromedae (ω And, ω Andromedae) is the Bayer designation for a slowly co-rotating binary star system in the northern constellation of Andromeda. Parallax measurements made during the Hipparcos mission make this system to be approximately from Earth. Its apparent visual magnitude is +4.83, which makes it bright enough to be seen with the naked eye. The primary component has a stellar classification of F5 IVe.
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HD 73389 is a binary star system in the constellation Carina. It has the Bayer designation e2 Carinae; HD 73389 is the identifier from the Henry Draper Catalogue. This system is visible to the naked eye as a point of light with a combined apparent visual magnitude of +4.84. Based on parallax measurements, it is located at a distance of approximately 225 light years from the Sun.
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HR 3220 is a binary star system in the southern constellation of Carina. It has the Bayer designation B Carinae; HR 3220 is the designation from the Bright Star Catalogue. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude of 4.75. Based upon parallax measurements, it is located at a distance of 59 light years from the Sun.
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V376 Carinae is a binary star system in the southern constellation of Carina. It has the Bayer designation b1 Carinae; V376 Carinae is the variable star designation. The system is visible to the naked eye as a faint point of light with a combined apparent magnitude of +4.69. The distance to this system from the Sun is approximately 650 light years based on parallax.
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HD 69863 is a binary star system in the southern constellation of Carina. It is visible to the naked eye as a dim point of light with a combined apparent visual magnitude of 5.16. The system is located at a distance of about255 light years from the Sun based on parallax. The dual nature of this system was announced in 1832 by German astronomer Carl Rümker.
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Mu Aquarii, Latinized from μ Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of 4.7. Based upon parallax measurements, the distance to this system is about . Mu Aquarii is a spectroscopic binary with an orbital period of 1,566 days and an eccentricity of 0.23.
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W Corvi is an eclipsing binary star system in the constellation Corvus, ranging from apparent magnitude 11.16 to 12.5 over 9 hours. Its period has increased by 1/4 second over a century. It is an unusual system in that its two stars are very close to each other yet have different surface temperatures and hence thermal transfer is not taking place as expected.
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69 Herculis is a binary star system in the northern constellation Hercules. It has the Bayer designation e Herculis, while 69 Herculis is the Flamsteed designation. This object is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 4.63. The distance to this system can be estimated from parallax measurements, which yields a range of 175 light years.
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Circinus X-1 is an X-ray binary star system that includes a neutron star. Observation of Circinus X-1 in July 2007 revealed the presence of X-ray jets normally found in black hole systems; it is the first of the sort to be discovered that displays this similarity to black holes. Circinus X-1 may be among the youngest X-ray binaries observed.
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Theta Hydrae, Latinized from θ Hydrae, is a binary star system in the constellation Hydra. It is visible to the naked eye with an apparent visual magnitude of 3.9. The star system has a high proper motion with an annual parallax shift of , indicating a distance of about . Theta Hydrae forms a double with a magnitude 9.9 star located at an angular separation of .
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HD 81799 (G Hydrae) is a suspected astrometric binary star system in the equatorial constellation of Hydra. It is visible to the naked eye with an apparent visual magnitude of 4.69. The distance to this system, as determined from an annual parallax shift of , is 164 light years. It is moving further away from the Earth with a heliocentric radial velocity of 29 km/s.
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54 Leonis is a binary star system in the zodiac constellation of Leo, located around 321 light years from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 4.30. As of 2017, the pair had an angular separation of along a position angle of 113°. They have a physical separation of around .
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10 Vulpeculae is an astrometric binary star system in the northern constellation of Vulpecula. It is faintly visible to the naked eye with an apparent visual magnitude of 5.497. The system is located roughly 330 light years from the Sun, as determined from an annual parallax shift of . It is moving closer to the Sun with a heliocentric radial velocity of −9.9 km/s.
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V4641 Sagittarii (V4641 Sgr) is a variable X-ray binary star system in the constellation Sagittarius. It is the source of one of the fastest superluminal jets in the Milky Way galaxy. In 1999 a violent X-ray outburst revealed it to contain a black hole. At the time, it was considered to be the closest known black hole to Earth, at a distance of approximately .
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Its distance has been estimated anywhere from one to six kpc. The General Catalogue of Variable Stars classifies it as an Orion variable, a pre-main sequence star, but other authors consider it to be a supergiant B[e] star. It has been confirmed to be a binary star system with the two stars separated by about 52 AU, but the nature of the companion is unknown.
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Sigma2 Gruis is a binary star system in the southern constellation of Grus. Its apparent visual magnitude is 5.86. The pair had an angular separation of 2.7 arc seconds along a position angle of 265°, as of 1991. Located around distant, the white-hued primary component is an A-type main-sequence star of spectral type A1V, a star that is currently fusing its core hydrogen.
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Gamma Centauri (γ Cen, γ Centauri) is a star in the southern constellation Centaurus. It has the proper name Muhlifain, not to be confused with Muliphein, which is γ Canis Majoris; both names derive from the same Arabic root. It is a binary star system about from Earth. The combined apparent visual magnitude of the pair is +2.17; individually they are third magnitude stars.
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BD+20°307 is a close binary star system approximately 300 light-years away in the constellation Aries. The system is surrounded by a dusty ring. The dust that orbits around several hundred main-sequence stars is cold and comes from a Kuiper-belt analogous region. In the Solar System the ongoing collisions between asteroids generate a tenuous cloud of dust known as the zodiacal light.
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A visual binary is a gravitationally bound binary star system that can be resolved into two stars. These stars are estimated, via Kepler's 3rd law, to have periods ranging from a few years to thousands of years. A visual binary consists of two stars, usually of a different brightness. Because of this, the brighter star is called the primary and the fainter one is called the companion.
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This is a single-lined spectroscopic binary star system. The pair have a nearly circular orbit with an eccentricity of at or below 0.03 and a period of . The primary has an value of , which only gives a lower bound for the semimajor axis a since the orbital inclination i to the line of sight is unknown. The system is a source for X-ray emission.
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15 Lyncis is a binary star system in the northern constellation of Lynx. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.35. Based on the system's parallax, it is located 178 light-years (54.7 parsecs) away. The pair are moving away from the Earth with a heliocentric radial velocity of +2 km/s.
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Zeta Centauri, Latinized from ζ Centauri, is a binary star system in the southern constellation of Centaurus. It has the proper name Alnair , from the scientific-Arabic Nayyir Badan Qanṭūris (نير بطن قنطورس), meaning "The Bright (Star) of the Body of the Centaur".ibid., p.28. With a combined apparent visual magnitude of +2.55, it is one of the brighter members of the constellation.
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This was the SM4 mission. An example of astrometry science with the Hubble FGS system is observations of the Low-Mass Binary star system L722-22. Observations were taken of the system in 1990s, and the data helped determine the mass of each of the components of L722-22, which is also known as LHS 1047 and GJ 1005. The FGS are white-light shearing interferometers.
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For example, there is no known complete solution for a spacetime with two massive bodies in it (which is a theoretical model of a binary star system, for example). However, approximations are usually made in these cases. These are commonly referred to as post-Newtonian approximations. Even so, there are several cases where the field equations have been solved completely, and those are called exact solutions.
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Groombridge 34 is a binary star system in the northern constellation of Andromeda. It was listed as entry number 34 in A Catalogue of Circumpolar Stars, published posthumously in 1838 by British astronomer Stephen Groombridge. Based upon parallax measurements taken by the Gaia spacecraft, the system is located about 11.6 light-years from the Sun. This positions the pair among the nearest stars to the Solar System.
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Using direct focussing observations of the non-thermal source in the extremely hard X-ray band that is spatially coincident with the star, they showed that the source of non-thermal X-rays varies with the orbital phase of the binary star system and that the photon index of the emission is similar to that derived through analysis of the γ-ray (gamma) spectrum.
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HD 40409 is a suspected astrometric binary star system in the southern constellation of Dorado. It is a faint system but visible to the naked eye with an apparent visual magnitude of 4.65. Based upon an annual parallax shift of , it is located 88 light years away from the Sun. It is moving further away with a heliocentric radial velocity of +25 km/s.
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HD 175535 is a binary star system in the northern circumpolar constellation of Draco. It has an apparent visual magnitude of 4.92, which is bright enough to be faintly visible to the naked eye. The system is located about 302 light years away, as determined from its annual parallax shift of . It is moving further from the Earth with a heliocentric radial velocity of +8.5 km/s.
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Gamma Canis Minoris (γ Canis Minoris) is a binary star system in the equatorial constellation Canis Minor. Its orange colour is obvious when seen through binoculars. The system is visible to the naked eye with a combined apparent visual magnitude of +4.33. Based upon an annual parallax shift of 10.25 mas as seen from Earth, this system is located about 320 light years from the Sun.
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Xi2 Canis Majoris, which is Latinized from ξ2 Canis Majoris, is an astrometric binary star system in the southern constellation of Canis Major. With an apparent visual magnitude of +4.54, it is visible to the naked eye. Based upon an annual parallax shift of , the system is approximately 390 light years distant from Earth. It is receding with a radial velocity of +26 km/s.
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Omega Eridani (ω Eri) is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude is 4.37. The distance to this star, as determined by the parallax method, is around 235 light years. This is a single-lined spectroscopic binary system with an orbital period of 3,057 days (8.4 years) and an eccentricity of 0.46.
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This star is considered a solar analog—meaning that it is photometrically analogous to the Sun. Like the Sun, it has a magnetic activity cycle. It shares a common proper motion through space with the spectroscopic binary star system HD 122742, and in the past the three may have formed a triple star system. In the Bright Star Catalogue, it was noted as having an infrared excess.
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13 Comae Berenices is a probable binary star system in the northern constellation of Coma Berenices. It has an apparent visual magnitude of 5.17, which is bright enough to be faintly visible to the naked eye. With an annual parallax shift of 12.33 mas, it is located around 260 light years from the Sun. It is member of the nearby Coma Star Cluster (Melotte 111).
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BY Draconis is a multiple star system in the constellation Draco, consisting of at least three components. Components A and B are main sequence stars, and form a close binary star system with a short orbital period of only 5.98 days. Their individual spectroscopic classifications are dK5e and dK7e. They form the prototype of a class of variable stars known as BY Draconis variables.
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Xi Aquarii (ξ Aquarii, abbreviated Xi Aqr, ξ Aqr) is a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.7. Based upon parallax measurements made during the Hipparcos mission, this system lies at a distance of around from the Sun. The two components are designated Xi Aquarii A (also named Bunda) and B.
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17 Leporis is a binary star system in the southern constellation of Lepus.§1, Verhoelst, van Aarle, and Acke, 2007. It has an overall apparent visual magnitude which varies between 4.82 and 5.06, making it luminous enough to be visible to the naked eye as a faint star. The variable star designation for this system is SS Leporis, while 17 Leporis is the Flamsteed designation.
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Eta Horologii (η Horologii, η Hor) is a binary star system in the southern constellation of Horologium. It is visible to the naked eye with a combined apparent visual magnitude of 5.31. Based upon an annual parallax shift of 21.95 mas as seen from Earth, it is located around 149 light years from the Sun. The orbit for this pair is not yet well constrained.
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The Star Kingdom of Manticore is the star nation that occupies the Manticore binary star system. It is a monarchy and the current ruler is Queen Elizabeth III of the House of Winton. The binary Manticore System was located 512 light-years to the Galactic north of the Sol System and Earth. It contained three habitable planets: Gryphon, Sphinx, and the capital planet Manticore.
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Theta1 Crucis (θ1 Cru, Theta1 Crucis) is a spectroscopic binary star system in the southern constellation of Crux. It is visible to the naked eye with an apparent visual magnitude of 4.30m. The distance to this star, as determined using parallax measurements, is around 235 light years. The pair orbit each other closely with a period of 24.5 days and an eccentricity of 0.61.
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Xi Piscium (ξ Piscium) is an orange-hued binary star system in the zodiac constellation of Pisces. In 1690, the astronomer Johannes Hevelius in his Firmamentum Sobiescianum regarded the constellation Pisces as being composed of four subdivisions. Xi Piscium was considered to be part of the Linum Austrinum, the South Cord. The star is visible to the naked eye, having an apparent visual magnitude of 4.60.
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DD Microscopii, also known as CD-43 14304, is a binary star system in the constellation Microscopium. Its apparent magnitude is 11.0.SIMBAD, DD Microscopii (accessed 25 March 2015) It is a symbiotic star system composed of an orange giant of spectral type K2III and white dwarf in close orbit, with the smaller star ionizing the stellar wind of the larger star. The system is metal-poor.
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Nu2 Sagittarii (ν2 Sagittarii) is a binary star system in the zodiac constellation of Sagittarius. It is faintly visible to the naked eye, having an apparent visual magnitude of +4.98. Based upon a small annual parallax shift of 11.91 mas as seen from Earth, this system is located around 270 light years from the Sun. Nu2 Sagittarii has a high peculiar velocity of and is most likely a runaway star system.
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Beta Serpentis, Latinized from β Serpentis, is a binary star system in the constellation Serpens, in its head (Serpens Caput). It is visible to the naked eye with a combined apparent visual magnitude of +3.65. Based upon an annual parallax shift of 21.03 mas as seen from Earth, it is located around 155 light years from the Sun. The system is a member of the Ursa Major Moving Group.
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70 Pegasi is a binary star system in the northern constellation Pegasus. It is a faint star, visible to the naked eye under good seeing conditions, with an apparent visual magnitude of 4.56. The measured annual parallax shift measured from Earth's orbit is 18.65 mas, yielding a distance estimate of around 175 light years. The visual magnitude of the star is diminished by an extinction of due to interstellar dust.
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Theta Ursae Minoris, Latinized from θ Ursae Minoris, is a suspected binary star system that is visible to the naked eye in the northern circumpolar constellation of Ursa Minor. It is roughly 860 light years from Earth with an apparent visual magnitude of 5.0. The system is moving closer to the Sun with a radial velocity of −25 km/s. This is a probable spectroscopic binary with two roughly equal components.
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ADS 16402 is a binary star system, composed of two sun-like stars located approximately 525 light-years away in the constellation Lacerta. It was first identified by John Herschel in 1831. The two stars are separated by 11.26 arcseconds which leads to a projected separation of roughly 1500 astronomical units at the distance of ADS 16402. The star system is estimated to be 1.9 ± 0.6 billion years old.
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4 Aquarii (abbreviated 4 Aqr) is a binary star system in the constellation Aquarius, located approximately 198 light years away from the Sun. 4 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim, yellow- white hued star with a combined apparent visual magnitude of 5.99. The system is moving closer to the Earth with a heliocentric radial velocity of −21.5 km/s.
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Alpha Fornacis (α Fornacis, abbreviated Alpha For, α For) is a binary star system in the southern constellation of Fornax. It is the brightest star in the constellation and the only one brighter than magnitude 4.0. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 46 light-years (14 parsecs) distant from the Sun. Its two components are designated Alpha Fornacis A (officially named Dalim ) and B.
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Zeta Reticuli, Latinized from ζ Reticuli, is a wide binary star system in the southern constellation of Reticulum. From the southern hemisphere the pair can be seen with the naked eye as a double star in very dark skies. Based upon parallax measurements, this system is located at a distance of about from Earth. Both stars are solar analogs that have characteristics similar to those of the Sun.
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HD 41534 is a binary star system in the southern constellation of Columba. It is dimply visible to the naked eye with a combined apparent visual magnitude of 5.65. The distance to this system is approximately 950 light-years based on parallax, and it is receding from the Sun with a radial velocity of +93 km/s. This is a runaway star system with an unusually high peculiar velocity of .
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Beta Arietis has an apparent visual magnitude of 2.66. Based on parallax measurements, it is located at a distance of from Earth. This is a spectroscopic binary star system consisting of a pair of stars orbiting around each other with a separation that can not currently be resolved with a conventional telescope. However, the pair have been resolved using the Mark III Stellar Interferometer at the Mount Wilson Observatory.
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HD 202951 is a probable binary star system located in the northern constellation of Equuleus. It is near the lower limit of visibility to the naked eye, having an apparent visual magnitude of 5.97. The distance to this system can be estimated from the annual parallax shift of , yielding a value of roughly 1,190 light years. It is moving closer with a heliocentric radial velocity of −37 km/s.
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Phi Cygni, Latinized from φ Cygni, is a binary star system in the northern constellation of Cygnus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.70. The annual parallax shift is 12.25 mas as measured from Earth, which yields a distance estimate of around 266 light years. It is moving further from the Sun with a radial velocity of +4.5 km/s.
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This is a single-lined spectroscopic binary star system with an orbital period of 258.48 days and an eccentricity of 0.21. The primary, component A, is an evolved K-type giant star with a stellar classification of K0 III. It is a suspected barium star, which may indicate the orbiting companion, component B, is a white dwarf star. The measured angular diameter of the primary, after correction for limb darkening, is .
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U Aquilae is a binary star system in the constellation Aquila, Located approximately away from Earth. The primary star (component A) is a yellow supergiant with a radius of and a luminosity of . The secondary (component B) is a blue main-sequence star, twice the mass of the sun and around thirty times more luminous. It is hotter than the primary star at 9,300 K, but much smaller and fainter.
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16 Vulpeculae is a binary star system in the northern constellation Vulpecula. It has a combined apparent visual magnitude of 5.787, which is near the lower limit of visibility to the naked eye. Based upon an annual parallax shift of as seen from Earth's orbit, it is located about 222 light years away. The system is moving closer to the Sun with a heliocentric radial velocity of about −37 km/s.
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41 Aurigae is a binary star system located around 310–316 light years away from the Sun in the northern constellation of Auriga. It is visible to the naked eye as a dim, white-hued star with a combined apparent visual magnitude of 5.83. This system is moving further from the Earth with a heliocentric radial velocity of 31 km/s. It is a probable member of the Hyades Supercluster.
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7 Arietis (abbreviated 7 Ari) is a binary star system in the northern constellation of Aries. 7 Arietis is the Flamsteed designation. The pair have a combined apparent visual magnitude of 5.76, making it faintly visible to the naked eye from dark suburban skies. Based upon an annual parallax shift of 5.85 mas, it is approximately distant from the Earth, give or take a 40 light- year margin of error.
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23 Aquilae is a binary star system in the equatorial constellation of Aquila. 23 Aquilae is its Flamsteed designation. It is at a distance of about with an apparent visual magnitude of 5.10, which is bright enough to be faintly visible to the naked eye as an orange-hued star. The brightness of the star is diminished by 0.21 in magnitude because of extinction from interstellar dust and gas.
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Nu2 Boötis is a white-hued binary star system in the northern constellation of Boötes. It is faintly visible to the naked eye with a combined apparent visual magnitude of 5.02. Based upon an annual parallax shift of 7.86 mas as seen from the Earth, it is located roughly 415 light years from the Sun. The system is moving closer to the Sun with a radial velocity of −16.6 km/s.
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83 Aquarii (abbreviated 83 Aqr) is a binary star system in the equatorial constellation of Aquarius. 83 Aquarii is its Flamsteed designation, though it also bears the Bayer designation of h Aquarii. The combined apparent visual magnitude of the pair is 5.43, which is faintly visible to the naked eye. Based upon an annual parallax shift of 15.57 milliarcseconds, it is located at a distance of around from Earth.
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32 Aquarii is a binary star system in the zodiac constellation of Aquarius. 32 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.29. This system is moving away from the Earth with a heliocentric radial velocity of +19 km/s, and is a possible member of the corona of the Ursa Major flow.
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Zeta Cygni (ζ Cyg) is a binary star system in the northern constellation of Cygnus, the swan. It has an apparent visual magnitude of 3.26 and, based upon parallax measurements, is about away. The primary component, ζ Cyg A is a giant star with a spectral type of G8 IIIp. Its most likely status is as a red clump giant, an evolved star that has begun core helium fusion.
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1 Boötis (1 Boo) is a binary star system in the northern constellation of Boötes, located 318 light years away from the Sun. It is visible to the naked eye as a dim, white-hued star with a combined apparent visual magnitude of 5.71. The pair had an angular separation of as of 2008. It is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.
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20 Leonis Minoris is a binary star system in the northern constellation of Leo Minor. It is faintly visible to the naked eye, having an apparent visual magnitude of +5.4. Based upon an annual parallax shift of 66.46 mas, it is located 49 light years from the Sun. The star has a relatively high proper motion and is moving away from the Sun with a radial velocity of +56 km/s.
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Nu Draconis (also known as ν Dra, ν Draconis, or traditionally as Kuma ) is a double star in the constellation Draco. The respective components are designated ν1 Draconis and ν2 Draconis. The second component is a spectroscopic binary star system. This star, along with β Dra (Rastaban), γ Dra (Eltanin), μ Dra (Erakis) and ξ Dra (Grumium) were Al ʽAwāïd, "the Mother Camels", which was later known as the Quinque Dromedarii.
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Psi Centauri, which is Latinized from ψ Centauri, is a binary star system in the southern constellation of Centaurus. It is visible to the naked eye with a baseline apparent visual magnitude of +4.05. The distance to this system is approximately 259 light years based on parallax. The radial velocity is poorly constrained, but it appears to be slowly drifting away from the Sun at the rate of +2 km/s.
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The planet orbits in a circumbinary orbit around a (G-type) and (M-type) binary star system. The stars orbit each other about every 7.45 days. The stars have masses of 1.04 and 0.35 and radii of 0.96 and 0.35 , respectively. They have temperatures of 5636 K and 3357 K. Based on the stellar characteristics, an estimated age of 4–5 billion years for the system is possible.
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Delta2 Telescopii is a blue-white hued binary star system in the southern constellation of Telescopium. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.05. The distance to this system, as determined with an annual parallax shift of 2.73 mas, is roughly 1,200 light years. At that distance, the visual magnitude of the star is diminished by an extinction of 0.36 due to interstellar dust.
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Kepler-47 is a binary star system with three exoplanets in orbit around the pair of stars located about 1055 parsecs (3,442 light years) away from Earth. The first two planets announced are designated Kepler-47b, and Kepler-47c. Kepler-47 is the first circumbinary multi-planet system discovered by the Kepler mission. The outermost of the planets is a gas giant orbiting within the habitable zone of the stars.
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Mu2 Octantis (μ2 Oct) is a binary star system of two G-type main-sequence stars. It shares the designation μ with μ1 Octantis, from which it is separated by 50 arcminutes. The primary star (A) is HD 196067, whose data is in the starbox. The secondary star (B) is HD 196068 (HIP 102128, LTT 8160), another G-type main-sequence star with an apparent magnitude of 7.18.
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Phi Aquilae, Latinized from φ Aquilae, is the Bayer designation of a binary star system in the equatorial constellation of Aquila. It has an apparent visual magnitude of +5.28 and is visible to the naked eye. With an annual parallax shift of 14.86 mas, this star is located at a distance of approximately from Earth. Phi Aquilae is a single-lined spectroscopic binary with an orbital period of 3.32068 days.
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Mu1 Gruis, Latinized from μ1 Gruis, is a binary star system in the southern constellation of Grus. It is visible to the naked eye with a combined apparent visual magnitude of 4.79. The distance to this system, as determined using an annual parallax shift of 11.44 mas as seen from the Earth, is around 275 light years. It is drifting closer with a heliocentric radial velocity of −5 km/s.
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Gliese 3685 is a star in the constellation of Leo. It is extremely faint; its apparent magnitude is 13.3, and can only be seen with a ten-inch (25 cm) telescope (see Limiting magnitude). Based on a parallax of 50.30 milliarcseconds, the system is located 65 light years (20 parsecs) away from the Earth. This is a part of a binary star system consisting of two components separated by 24″.
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Eggleton and Tokovinin (2008) listed this as a suspected binary star system consisting of two roughly equal components. It appears as an ageing red giant with a stellar classification of M0III. This is a suspected semiregular variable star with a very small amplitude and a period of 40 days or more. Having exhausted the supply of hydrogen at its core, it has expanded to 44 times the Sun's radius.
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The planet orbits in a circumbinary orbit around a (G-type) and (M-type) binary star system. The stars orbit each other about every 7.45 days. The stars have masses of 1.04 and 0.35 and radii of 0.96 and 0.35 , respectively. They have temperatures of 5636 K and 3357 K. Based on the stellar characteristics and orbital dynamics, an estimated age of 4–5 billion years for the system is possible.
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30 Herculis is a binary star system in the northern constellation of Hercules. It has the Bayer designation g Herculis, while 30 Herculis is the Flamsteed designation. This system is visible to the naked eye as a faint, red-hued point of light with a baseline apparent visual magnitude of 4.83. Based upon a measured parallax of , it is located around 354 light years away from the Sun.
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II Pegasi is a binary star system in the constellation of Pegasus with an apparent magnitude of 7.4 and a distance of 130 light years. It is a very active RS Canum Venaticorum variable (RS CVn), a close binary system with active starspots. The primary (II Pegasi A) is a cool subgiant, an orange K-type star. It has begun to evolve off the main sequence and expand.
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Delta Horologii (δ Horologii) is a binary star system in the constellation Horologium. It is visible to the naked eye with a combined apparent visual magnitude of 4.93. As of 2014, the pair had an angular separation of 0.20 arc seconds along a position angle of 24°. Based upon an annual parallax shift of 18.24 mas as seen from Earth, it is located 179 ± 4 light years from the Sun.
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Teal'c is a Jaffa from the planet Chulak, a planet orbiting a binary star system. Jaffa have a human appearance but have an abdominal pouch which serves as an incubator for a larval Goa'uld. The larval symbiote grants enhanced strength, health, healing, and longevity. Teal'c states he is 101 years old in season 4's "The Light", and ages an additional 50 years in season 10's "Unending".
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HR 4458 is a binary star system in the equatorial constellation of Hydra. It has the Gould designation 289 G. Hydrae; HR 4458 is the Bright Star Catalogue designation. At a distance of 31.13 light years, it is the closest star system to the solar system within this constellation. This object is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.97.
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A binary star system consists of two stars that orbit around their common centre of mass. The movements of both stars lie on a common orbital plane in space. When this plane is very closely aligned with the location of an observer, the stars can be seen to pass in front of each other. The result is a type of extrinsic variable star system called an eclipsing binary.
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The maximum luminosity of an eclipsing binary system is equal to the sum of the luminosity contributions from the individual stars. When one star passes in front of the other, the luminosity of the system is seen to decrease. The luminosity returns to normal once the two stars are no longer in alignment. The first eclipsing binary star system to be discovered was Algol, a star system in the constellation Perseus.
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Psi2 Orionis a binary star system in the equatorial constellation of Orion. It has an apparent visual magnitude of 4.60, indicating that it is visible to the naked eye. Based upon an annual parallax shift of 2.87 mass, it is roughly 1,100 light years distant from the Sun. This is a double-lined spectroscopic binary, which means that the individual absorption lines of both components can be discerned.
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A 2008 study concluded that the GSC 06200-00648 system (among others) is a binary star system allowing even more accurate determination of stellar and planetary parameters. TrES-4 orbits its primary star every 3.543 days and eclipses it when viewed from Earth. The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to 6.3°.
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The Captain and Humvee feel betrayed, but untie her. Searching the ship's database, the Captain and the Professor (Grant Swanby), who uses a wheelchair, discover that the legendary vampire hunter Abraham Van Helsing was one of the Captain's ancestors. The Professor believes Orlock will seek revenge against the Captain. The Captain learns how vampires can be stopped and decides to steer the Demeter on a course towards a binary star system.
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Phi Phoenicis, Latinized from φ Phoenicis, is a binary star system in the southern constellation of Phoenix. It is faintly visible to the naked eye with an apparent visual magnitude of 5.1. Based upon an annual parallax shift of 10.48 mas as seen from Earth, it is located around 310 light years from the Sun. It is moving away from the Sun with a radial velocity of 10.4 km/s.
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Tau2 Lupi, Latinized from τ2 Lup, is a binary star system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.34. Based upon an annual parallax shift of 10.22 mas as seen from Earth, it is located around 319 light years from the Sun. The two components orbit each other with a period of 26.2 years and a high eccentricity of 0.94.
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42 Persei is a binary star system in the northern constellation of Perseus. It has the Bayer designation n Persei, while 42 Persei is the Flamsteed designation. The system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.11. It is located around distant from the Sun, but is drifting closer with a radial velocity of −12.4 km/s.
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HD 114837 is a suspected binary star system in the southern constellation of Centaurus. The brighter star is faintly visible to the naked eye with an apparent visual magnitude of 4.90. It has a magnitude 10.2 candidate common proper motion companion at an angular separation of , as of 2014. The distance to this system, based on an annual parallax shift of as seen from Earth's orbit, is 59.3 light years.
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However, the star seems to be at most 20 million years old, which implies that it is a blue straggler, a star born from the merger of a binary star system, which was earlier ejected from the center of the Milky Way. In order for this to happen, there must have originally been a three-star system, or else there were two black holes and just the two stars.
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Tau4 Eridani (τ4 Eridani, τ4 Eri) is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.65. The distance to this star can be estimated using the parallax method, which yields a value of roughly 300 light years. This is an evolved red giant star currently on the asymptotic giant branch with a stellar classification of M3/4 III.
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HD 165189 and HD 165190 are components of a visual binary star system located 145 light years away in the southern constellation of Corona Australis. It is visible to the naked eye with the primary having an apparent visual magnitude of . The system is a member of the Beta Pictoris Moving Group. The pair orbit each other with a period of 450 years and a large eccentricity of 0.650.
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This is a binary star system with an orbital period of 52.1 days and an eccentricity of 0.22. Only the primary star can be directly detected, via Doppler shifts or perturbations around the system's barycenter. Using spectroscopy and astrometry, the nature of the secondary star can be inferred. The primary star is an F-type main-sequence star with a stellar classification of F8V, 4% more massive than the Sun.
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Epsilon Scuti, Latinized from ε Scuti, is a probable astrometric binary star system in the constellation Scutum. It is faintly visible to the naked eye with an apparent visual magnitude of +4.88. Based upon an annual parallax shift of 6.06 mas as seen from Earth, it is located approximately 540 light years from the Sun. It is moving closer to the Sun with a radial velocity of −9.8 km/s.
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Epsilon Reticuli (Epsilon Ret, ε Reticuli, ε Ret) is a double star approximately 59 light-years away in the constellation of Reticulum. The primary component is an orange subgiant, while the secondary is a white dwarf. The two stars share a common motion through space and hence most likely form a binary star system. The brighter star should be easily visible without optical aid under dark skies in the southern hemisphere.
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Gamma Sextantis, Latinized as γ Sextantis, is a binary star system in the equatorial constellation of Sextans. The combined apparent visual magnitude of the system is 5.05, which means it is faintly visible to the naked eye. The annual parallax shift is 11.75 mas, indicating a distance of around 280 light years. The two components orbit each other with a period of 77.55 years and a high eccentricity of 0.691.
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14 Lacertae is a binary star system in the northern constellation Lacerta, located around 1,600 light years away. It has the variable star designation V360 Lacertae; 14 Lacertae is the Flamsteed designation. The system is barely visible to the naked eye in good seeing conditions, having a peak apparent visual magnitude of 5.91. It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.
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VV Cephei, also known as HD 208816, is an eclipsing binary star system located in the constellation Cepheus, approximately 5,000 light years from Earth. It is both a B[e] star and shell star. VV Cephei is an eclipsing binary with the second longest known period. A red supergiant fills its Roche lobe when closest to a companion blue star, the latter appearing to be on the main sequence.
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Zeta1 Antliae is the Bayer designation for a binary star system in the southern constellation of Antlia. Based upon parallax measurements, the pair are located at a distance of roughly from Earth. They have apparent magnitudes of +6.20 and +7.01 and are separated by 8.042 arcseconds. The apparent magnitude of the combined system is +5.76, which is bright enough to be seen with the naked eye in suitably dark skies.
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Psi6 Aurigae, Latinized from ψ6 Aurigae, is a spectroscopic binary star in the northern constellation of Auriga. It is a dim, naked eye star with an apparent visual magnitude of +5.22. Based upon a measured annual parallax shift of , it is approximately distant from the Earth. This is a single-lined spectroscopic binary star system with an orbital period of 5,996 days (16.4 years) and an eccentricity of 0.044.
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Psi Velorum (ψ Vel, ψ Velorum) is a binary star system in the southern constellation of Vela. Based upon an annual parallax shift of 53.15 mas as seen from Earth, it is located 61.4 light years from the Sun. It is visible to the naked eye with a combined apparent visual magnitude of +3.58. The motion of this system through space makes it a candidate member of the Castor stellar kinematic group.
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52 Sagittarii is a binary star system in the southern constellation of Sagittarius. It has the Bayer designation h2 Sagittarii, while 52 Sagittarii is the Flamsteed designation. This system is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude of 4.59. It is located approximately 190 light years away based on parallax, but is drifting closer with a radial velocity of −19 km/s.
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Psi Virginis (ψ Vir, ψ Virginis) is a suspected binary star system in the zodiac constellation of Virgo. It can be seen with the naked eye and has an apparent visual magnitude of +4.80. Based upon the annual parallax shift of 5.99 milliarcseconds, the distance to this star is roughly 540 light years. The angular size of Psi Virginis was measured on December 26, 1975 during an occultation by the Moon, yielding the estimate .
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Theta1 Sagittarii (θ1 Sagittarii) is a close binary star system in the zodiac constellation of Sagittarius. It is visible to the naked eye with an apparent visual magnitude of 4.37. Based upon an annual parallax shift of 6.29 mas as seen from Earth, this star is located around 520 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.24 due to interstellar dust.
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68 Ophiuchi is a binary star system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint star with an apparent visual magnitude of 4.42. The system is located around distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +6 km/s. This is a spectroscopic binary with an orbital period of 177 years and an eccentricity of 0.83.
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74 Cygni is a visual binary star system in the northern constellation Cygnus, located around 249 light years distant from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.04. The pair orbit each other with a period of and an eccentricity of 0.5. The system is a source of X-ray emission, which is most likely coming from the secondary component.
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Lightcurve of Gamma Persei's 2019 eclipse recorded by NASA's Transiting Exoplanet Survey Satellite (TESS). Gamma Persei (Gamma Per, γ Persei, γ Per) is a binary star system in the constellation Perseus. The combined apparent visual magnitude of the pair is +2.9, making it the fourth-brightest member of the constellation. The distance to this system has been measured using the parallax technique, giving an estimate of roughly with a 4% margin of error.
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RR Ursae Minoris, or RR UMi, is a binary star system in the northern circumpolar constellation of Ursa Minor. It can be viewed with the naked eye, typically having an apparent visual magnitude of around 4.710. Based upon an annual parallax shift of as seen from Earth's orbit, it is located 330 light years away. The system is moving further from the Sun with a heliocentric radial velocity of +6 km/s.
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Its two brightest stars, Delta Crateris of magnitude 3.56 and Alpha Crateris of magnitude 4.07, are ageing orange giant stars that are cooler and larger than the Sun. Beta Crateris is a binary star system composed of a white giant star and a white dwarf. Seven star systems have been found to host planets. A few notable galaxies, including Crater 2 and NGC 3981, and a famous quasar lie within the borders of the constellation.
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Delta Columbae is a binary star system in the constellation Columba. It can be seen with the naked eye having an apparent visual magnitude of 3.85. The distance to this system, based upon an annual parallax shift of 13.94 mas, is around 234 lightyears. Delta Columbae was a latter designation of 3 Canis Majoris, as the early astronomers Johann Bayer and John Flamsteed did not include the constellation Columba in their star charts.
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Psi Crateris, Latinized from ψ Crateris, is the Bayer designation for a visual binary star system in the southern constellation of Crater. It is faintly visible to the naked eye with an apparent visual magnitude of 6.13. According to the Bortle scale, it requires dark suburban or rural skies to view. Based upon an annual parallax shift of 6.5 mas, the system is located approximately 500 light years away from the Sun.
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F Centauri is a suspected astrometric binary star system in the southern constellation of Centaurus. It has a reddish hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around +5.01. The system is located at a distance of approximately 450 light years from the Sun based on parallax, and it has an absolute magnitude of −0.87. O. J. Eggen flagged this star as a member of the Hyades Supercluster.
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Light curve of AX Circini recorded by NASA's Transiting Exoplanet Survey Satellite (TESS) AX Circini is a binary star system in the southern constellation of Circinus. It has a nominal magnitude of 5.91, which is bright enough to be visible to the naked eye. Based upon an annual parallax shift of , it is located roughly 1,900 light years from the Earth. The system is moving closer with a heliocentric radial velocity of −21 km/s.
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34 Persei is a binary star system in the northern constellation of Perseus. It is visible to the naked eye as a faint, blue-white hued point of light with a combined apparent visual magnitude of 4.67. The system is located approximately 540 light years away from the Sun based on parallax, but it is drifting closer with a radial velocity of −3.5 km/s. It is a likely member of the Alpha Persei Cluster.
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This is a single-lined spectroscopic binary star system with an orbital period of 15.8 days and an eccentricity of 0.31. The primary member, component A, is an A-type main sequence star with a stellar classification of A1VsSi:. The stellar spectrum has the appearance of a hot Am star, showing overabundances of many iron-peak and heavier elements, but an underabundance of helium. In particular, it has an abnormal abundance of silicon.
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Pi2 Orionis (π2 Ori, π2 Orionis) is the Bayer designation for a solitary star in the equatorial constellation of Orion. Although the Bright Star Catalogue lists this as a spectroscopic binary star system, this does not appear to be the case. It is visible to the naked eye with an apparent visual magnitude of 4.35. Based upon an annual parallax shift of 14.53 mas, it is located roughly 224 light years away from the Sun.
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Kappa1 Apodis, Latinized from κ1 Apodis, is the Bayer designation for a binary star system in the southern circumpolar constellation of Apus. Based upon parallax measurements, it is located roughly from Earth. The combined apparent visual magnitude of the system is 5.52, indicating that this is a faint, naked eye star that can be viewed in dark suburban skies. It is moving away from the Sun with a radial velocity of +62 km/s.
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GRS 1915+105 or V1487 Aquilae is an X-ray binary star system which features a regular star and a black hole. It was discovered on August 15, 1992 by the WATCH all-sky monitor aboard Granat. "GRS" stands for "GRANAT source", "1915" is the right ascension (19 hours and 15 minutes) and "105" reflects the approximate declination (10 degrees and 56 arcminutes). The near-infrared counterpart was confirmed by spectroscopic observations.
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22 Vulpeculae is a binary star system in the northern constellation Vulpecula. Based on its parallax, it is located some 1,900 light-years away, and it has an apparent magnitude of about 5.176, making it visible to the naked eye. The system is moving closer to the Earth with a heliocentric radial velocity of −23 km/s. The pair have an orbital period of in what is assumed to be a circular orbit.
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Tau Cygni, Latinised from τ Cygni, is a binary star system in the constellation Cygnus, approximately 69 light years away from Earth. This visual binary system has a period of 49.6 years. The main star, 4th magnitude GJ 822.1 A, is a yellowish white subgiant star of the spectral type F2IV. It therefore has a surface temperature of 6,000 to 7,500 kelvins and is larger, hotter, and several times as bright as the Sun.
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83 Ursae Majoris is a candidate binary star system in the northern circumpolar constellation of Ursa Major. This is a semiregular variable star, like Mira; for that reason it has been given the variable star designation IQ Ursae Majoris. It ranges in brightness from apparent visual magnitude 4.69 to 4.75. Percy and Au (1994) identified it as a small amplitude red variable with an irregular behavior, having a characteristic time scale of 20 days.
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Based upon its parallax measurement of , this star is located approximately 520 light years from Earth. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.89. 1 Aurigae is moving closer to the Earth with a heliocentric radial velocity of −25 km/s. This is a possible binary star system, based upon the status of the visible component as a mild barium star.
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89 Aquarii (abbreviated 89 Aqr) is a binary star system in the equatorial constellation of Aquarius. 89 Aquarii is the Flamsteed designation, though it also bears the Bayer designation c3 Aquarii. database record, HD-DM-GC-HR-HIP- Bayer-Flamsteed Cross Index, N. D. Kostjuk, Institute of Astronomy of Russian Academy of Sciences, 2002; CDS ID IV/27A. The apparent visual magnitude of +4.69 is bright enough to be seen with the naked eye.
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1 Aquarii is a binary star system in the zodiac constellation of Aquarius, about 257 light years away from the Sun. 1 Aquarii is the Flamsteed designation. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.151, located a degree north of the celestial equator. The system is moving closer to the Earth with a heliocentric radial velocity of −41 km/s.
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47 Andromedae is a binary star system in the northern constellation of Andromeda. The designation is from the star catalogue of John Flamsteed, first published in 1712. The system has a combined apparent visual magnitude of 5.60, which is just bright enough to be faintly visible to the naked eye under good seeing conditions. The distance to this system, as determined from an annual parallax shift of 15.9805 mas, is about 204 light years.
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9 Andromedae, abbreviated 9 And by convention, is a variable binary star system in the northern constellation Andromeda. 9 Andromedae is the Flamsteed designation, while it bears the variable star designation AN Andromedae, or AN And. The maximum apparent visual magnitude of the system is 5.98, which places it near the lower limit of visibility to the human eye. Based upon an annual parallax shift of , it is located 460 light years from the Earth.
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66 Andromedae is a binary star system in the northern constellation of Andromeda, near the northern border with Perseus. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. It has a combined apparent magnitude of 6.16, which is near the lower limit of stars that are visible to the naked eye under good seeing conditions. An annual parallax shift of provides a distance estimate of 178 light years.
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6 Boötis is a binary star system in the northern constellation of Boötes, located around 460 light years away from the Sun. It has the Bayer designation e Boötis; 6 Boötis is the Flamsteed designation. The system is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.92. It is moving closer to the Earth with a heliocentric radial velocity of −3 km/s.
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47 Boötis is a binary star system in the northern constellation of Boötes, located 261 light years away from the Sun. It has the Bayer designation k Boötis; 47 Boötis is the Flamsteed designation. The system is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.58. It is moving closer to the Earth with a heliocentric radial velocity of −13 km/s.
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At its present distance, the visual magnitude is diminished by an extinction factor of 0.135 due to interstellar dust. Xi Cancri is a single-lined spectroscopic binary star system with an orbital period of 4.66 years, an eccentricity of 0.06, and a semimajor axis of 0.01 arcseconds. The primary, Xi Cancri A, is a yellow G-type giant with an apparent magnitude of +5.70. Its companion, Xi Cancri B, is of magnitude 6.20.
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1 Centauri, or i Centauri, is a yellow-white hued binary star system in the southern constellation Centaurus. It can be seen with the naked eye, having an apparent visual magnitude of +4.23. Based upon an annual parallax shift of 51.54 mas as seen from Earth's orbit, it is located 51.5 light years from the Sun. The system is moving closer to the Sun with a radial velocity of −21.5 km/s.
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Upsilon2 Centauri (υ2 Centauri) is a binary star system in the southern constellation Centaurus. It is visible to the naked eye with an apparent visual magnitude of +4.33. Based upon an annual parallax shift of just 2.57 mas as seen from Earth, this star is located roughly 1,300 light years from the Sun. Relative to its neighbors, the system has a peculiar velocity of and it may form a runaway star system.
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This is not a binary star system in the sense of having a gravitationally-bound stellar companion. However, in early 2004, a brown dwarf companion Nu Ophiuchi b was discovered. This sub-stellar companion has at least 21.9 times the mass of Jupiter and takes 536 days (1.47 years) to complete an orbit. A second brown dwarf companion was discovered in 2010, orbiting further from the star with a period of 3,169 days (8.68 years).
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Delta1 Telescopii is a blue-white hued binary star system in the southern constellation of Telescopium. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.94. Based upon an annual parallax shift of 4.61 mas as seen from Earth, this system is roughly 710 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.29 due to interstellar dust.
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Sigma Geminorum (σ Gem) is a binary star system in the constellation Gemini, just to the northeast of Pollux. It is visible to the naked eye with an apparent visual magnitude of 4.20. Based upon an annual parallax shift of 26.08 mas, it is located 125 light years from the Sun. Sigma Geminorum is a single-lined spectroscopic binary, which means that the spectrum of only one of the components can be discerned.
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HD 158614 is a spectroscopic binary star system approximately 60 light-years away in the constellation of Ophiuchus. This system is in the Zeta Herculis moving group, which is of low metallicity stars, 5 billion years old. Besides ζ Herculis, the group includes δ Trianguli, ζ Reticuli, 1 Hydrae, Gl 456, φ2 Pavonis, and GJ 9079. This binary was included in a search for brown dwarfs that turned up no large companions.
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HD 170469 is a probable binary star system in the equatorial constellation of Ophiuchus. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.21. The system is located at a distance of 197 light years away from the Sun based on parallax. It is drifting closer with a radial velocity of −59 km/s, and is expected to come to within in about 959,000 years.
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HD 11964 is a binary star system located 110 light-years away from the Sun in the equatorial constellation of Cetus. It is visible in binoculars or a telescope but is too faint to be seen with the naked eye, having an apparent visual magnitude of 7.51. The system is drifting closer to the Sun with a radial velocity of −9 km/s. Two extrasolar planets have been confirmed to orbit the primary.
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30 Geminorum is a suspected astrometric binary star system in the northern zodiac constellation of Gemini. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.49. The distance to this star, as estimated through the use of parallax, is about 299 light years. It is drifting further away from the Sun with a heliocentric radial velocity of +9.5 km/s.
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AN Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major. It is a variable star, with AN Ursae Majoris being the variable star designation, and ranges in brightness from 14.90 down to 20.2. Even at its peak brightness though, the system is much to faint to be visible to the naked eye. Based on parallax measurements, the system is located roughly 1,050 light years away from the Sun.
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HD 81817 is a binary star system in the northern circumpolar constellation of Draco. It has an orange hue and is visible to the naked eye with an apparent visual magnitude of 4.28. The system is located at a distance of approximately 990 light years from the Sun based on parallax, and is drifting closer with a radial velocity of −7 km/s. It is a member of the IC 2391 moving group.
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2MASS J18082002−5104378 (abbreviated J1808−5104) is an ultra metal-poor (UMP) binary star system, in the constellation Ara, about from Earth, and is a single-lined spectroscopic binary (SB1). It is one of the oldest stars in the universe, about 13.53 billion years old, possibly one of the first stars, a star made almost entirely of materials released from the Big Bang. A tiny unseen companion, a low-mass UMP star, is particularly unusual.
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It shines with 4.6 times the luminosity of the Sun. The outer atmosphere is radiating this energy at an effective temperature of 6,725 K, giving it the yellow-white hue of an F-type star. There is some evidence that this may be a binary star system consisting of two stars with identical masses. Examination of Lambda Arae with the Spitzer Space Telescope shows an excess of infrared emission at a wavelength of 70 μm.
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16 Lyrae is a suspected astrometric binary star system in the constellation Lyra, located 126 light years away from the Sun based on parallax. It is visible to the naked eye as a dim, white-hued star with a combined apparent visual magnitude of 5.00. The system is moving further away from the Earth with a heliocentric radial velocity of +5 km/s. It is a suspected member of the Ursa Major Moving Group stream.
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Iota Arietis (ι Ari, ι Arietis) is the Bayer designation for a binary star system in the northern constellation of Aries. It has an apparent visual magnitude of 5.117; bright enough to be dimly seen with the naked eye. Parallax measurements made during the Hipparcos mission yield an estimated distance of from Earth. This is a spectroscopic binary system with an orbital period of 1,568 days (4.3 years) and an eccentricity of 0.36.
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HD 70930 is a binary star system in the southern constellation of Vela. It has the Bayer designation B Velorum, while HD 70930 is the star's identifier in the Henry Draper catalogue. With a combined apparent visual magnitude of 4.79, it is visible to the naked eye as a faint point of light. The distance to this system is approximately 1,700 light years based on parallax, and it has an absolute magnitude of −3.74.
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Delta1 Lyrae, Latinized from δ1 Lyrae, is a binary star system in the constellation Lyra, approximately 1,100 light years away from Earth. The two stars complete an orbit around each other about once every 88 days. They are a spectroscopic binary, meaning the separation between the two is very small, and their orbital velocity is very high. The primary member, component A, is a bluish white main-sequence star of the spectral type B2.5V.
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Kappa Aquarii is most probably a wide binary star system. The brighter component is a giant star with a stellar classification of K2 III. It has exhausted the supply of hydrogen at its core and has expanded to 13 times the radius of the Sun. It is radiating 60 times the Sun's luminosity from its outer envelope at an effective temperature of 4,581 K, giving it the orange- hued glow of a K-type star.
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Alpha Octantis is a binary star system in the constellation of Octans. The name is Latinized from α Octantis. Despite being labeled the "alpha" star by Johann Bayer in his star atlas Uranometria, it is not the brightest star in the constellation – that title belongs to Nu Octantis. It is visible to the naked eye as a faint, yellow-white hued point of light with an overall apparent visual magnitude of approximately 5.13.
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In astronomy, a common envelope (CE) is gas that contains a binary star system. The gas does not rotate at the same rate as the embedded binary system. A system with such a configuration is said to be in a common envelope phase or undergoing common envelope evolution. During a common envelope phase the embedded binary system is subject to drag forces from the envelope which cause the separation of the two stars to decrease.
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Phi Aquarii, Latinized from φ Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of +4.223. Parallax measurements indicate its estimated distance from Earth is roughly , and it is drifting further away with a radial velocity of +2.5 km/s. The proximity of this star to the ecliptic means it is subject to lunar occultations.
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111 Herculis is a suspected astrometric binary star system located 92 light years from the Sun in the northern constellation Hercules. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.34. The system is moving nearer to the Earth with a heliocentric radial velocity of −45 km/s, and may come as close as in 537,000 years. According to Cowley et al.
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12 Hydrae is a probable astrometric binary star system located 202 light years away from the Sun in the equatorial constellation of Hydra. It has the Bayer designation D Hydrae; 12 Hydrae is the Flamsteed designation. This system is visible to the naked eye as a faint, yellow-hued star with a combined apparent visual magnitude of 4.32. It is moving closer to the Earth with a heliocentric radial velocity of −8.5 km/s.
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Pi Cassiopeiae, Latinized from π Cassiopeiae, is a close binary star system in the constellation Cassiopeia. It is visible to the naked eye with an apparent visual magnitude of +4.949. Based upon an annual parallax shift of 18.63 mas as seen from Earth, this system is located about 175 light years from the Sun. This is a double-lined spectroscopic binary system with an orbital period of nearly two days in a circular orbit.
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72 Ophiuchi is a binary star system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint, white-hued point of light with a combined apparent visual magnitude of 3.73. It is located approximately 86.9 light years away from the Sun based on parallax, but is moving closer with a heliocentric radial velocity of -23.9 km/s. As of 2008, the pair had an angular separation of .
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QV Normae, also known as Norma X-2, is a high mass X-ray binary star system in the constellation Norma. It varies between apparent magnitudes of 16.19 and 16.31. The X-ray source was first identified in the early 1970s. The nature of the system was discovered in 1978 by astronomers who aligned a visual source of a reddened hot blue-white star with the X-ray source 4U 1538 - 52.
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Beta Muscae, Latinized from β Muscae, is a binary star in the southern circumpolar constellation of Musca. With a combined apparent visual magnitude of 3.07, it is the second brightest star (or star system) in the constellation. Judging by the parallax results, it is located at a distance of roughly from the Earth. This is a binary star system with a period of about 194 years at an orbital eccentricity of 0.6.
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Gamma Librae (γ Librae, abbreviated Gamma Lib, γ Lib) is a suspected binary star system in the constellation of Libra. It is visible to the naked eye, having an apparent visual magnitude of +3.91. Based upon an annual parallax shift of 19.99 mas as seen from Earth, it lies 163 light years from the Sun. The primary component (designated Gamma Librae A) has been formally named Zubenelhakrabi , the traditional name of the system.
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Xi Phoenicis, Latinized from ξ Phoenicis, is a visual binary star system in the southern constellation of Phoenix. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.70. Based upon an annual parallax shift of 14.61 mas as measured from Earth, it is located around 223 light years from the Sun. The system is moving away from the Sun with a radial velocity of about +10 km/s.
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In addition to having the current southern pole star of Earth, Octans also contains the southern pole star of the planet Saturn, which is the magnitude 4.3 Delta Octantis. The Astronomical Society of Southern Africa in 2003 reported that observations of the Mira variable stars R and T Octantis were urgently needed. Three star systems are known to have planets. Mu2 Octantis is a binary star system, the brighter component of which has a planet.
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LB-1 is a binary star system in the constellation Gemini. It is composed of a B-type star and an unseen object that might be a black hole. If the star is an ordinary main sequence B-type star (with its luminosity in conflict with a mainstay astronomic satellite's parallax measurements), the companion which is strongly suspected to be solitary, would be a black hole having mass outside of ordinary single stellar evolution parameters.
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17 Sagittarii is a binary star system in the zodiac constellation of Sagittarius, located 675 light years from the Sun. With a combined apparent visual magnitude of 6.89 it is below the normal limit of visibility to the naked eye. The system is moving closer to the Earth with a heliocentric radial velocity of −14 km/s. J. Allen Hynek (1938) found an initial spectral type of G5 + A5 for the pair.
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Sigma Puppis (Sigma Pup, σ Puppis, σ Pup) is a binary star system in the southern constellation of Puppis. It has an apparent visual magnitude of 3.25, which is bright enough to be visible to the naked eye at night from the southern hemisphere. Through a telescope, it appears as a bright, orange-hued star with a nearby white companion. Parallax measurements indicate this star is located at a distance of about from Earth.
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Nu Leporis, Latinized from ν Leporis, is a probable astrometric binary star system in the constellation Lepus. It is visible to the naked eye as a faint star with an apparent visual magnitude of 5.29. Based upon an annual parallax shift of 7.70 mas as seen from the Earth, it is 420 light years from the Sun. The visible component is a B-type star with an estimated 3.3 times the mass of the Sun.
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The inner pair form a binary star system with an orbital period of 192 years and an eccentricity of 0.611. Both components are A-type main- sequence stars, indicating that they are generating energy through core hydrogen fusion. The brighter member of this pair, designated component A, is the primary for the system with a visual magnitude of 4.18 and a stellar classification of A0V. The secondary, component B, is magnitude 5.22 and class A4V.
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Gamma Cassiopeiae, Latinized from γ Cassiopeiae, is a star at the center of the distinctive "W" asterism in the northern circumpolar constellation of Cassiopeia. Although it is a fairly bright star with an apparent visual magnitude that varies from 1.6 to 3.0, it has no traditional Arabic or Latin name. It sometimes goes by the informal name Navi. Gamma Cassiopeiae is a Be star, a variable star, and a binary star system.
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Beta Octantis, Latinized from β Octantis, is a probable astrometric binary star system in the southern circumpolar constellation of Octans. It is faintly visible to the naked eye with an apparent visual magnitude of 4.13. Based upon an annual parallax shift of 21.85 mas as seen from Earth, it is located about 149 light years from the Sun. It is moving away from the Sun with a radial velocity of +19 km/s.
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Delta Cassiopeiae is a possible eclipsing binary star system consisting of a pair of stars that orbit about each other over a period of 759 days. The combined apparent visual magnitude of the two stars is 2.68, making it readily observable with the naked eye. Eclipses have been reported with a period of 759 days, when the brightness drops by 0.07 magnitudes. Modern studies have shown no brightness variations greater than 0.01 magnitudes.
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Beta Aurigae (Latinized from β Aurigae, abbreviated Beta Aur, β Aur), officially named Menkalinan , is a binary star system in the northern constellation of Auriga. The combined apparent visual magnitude of the system is 1.9, making it the second-brightest member of the constellation after Capella. Using the parallax measurements made during the Hipparcos mission, the distance to this star system can be estimated as , give or take a half- light-year margin of error.
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29 Vulpeculae is a suspected astrometric binary star system in the northern constellation Vulpecula. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.82. The system lies approximately 209 light years away from the Sun based on parallax, and is a member of the IC 2391 supercluster. It is moving closer to the Earth with a heliocentric radial velocity of −17 km/s.
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PSR B1620−26 is a binary star system located at a distance of 3,800 parsecs (12,400 light-years) in the globular cluster of Messier 4 (M4, NGC 6121) in the constellation of Scorpius. The system is composed of a pulsar (PSR B1620−26 A) and a white dwarf star (WD B1620−26) or PSR B1620−26 B). As of 2000, the system is also confirmed to have an exoplanet orbiting the two stars.
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45 Cancri is a binary star system in the zodiac constellation of Cancer, located 680 light years away from the Sun. It has the Bayer designation A1 Cancri; 45 Cancri is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star at an apparent visual magnitude of 5.62. The pair form a double-lined spectroscopic binary with an orbital period of and an eccentricity of 0.46.
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HD 22663 (y Eridani) is a candidate astrometric binary star system in the equatorial constellation of Eridanus. It is visible to the naked eye with an apparent visual magnitude of 4.57. Based upon an annual parallax shift of , it is located around 230 light years from the Sun. It is moving further away from the Earth with a heliocentric radial velocity of +11.5 km/s, having come within some 3.76 million years ago.
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39 Draconis is a wide binary star system in the northern circumpolar constellation of Draco. It has the Bayer designation b Draconis, while 39 Draconis is the Flamsteed designation. This system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.0. Parallax measurements made by the Hipparcos spacecraft put it at a distance of 184 light-years, or 56 parsecs away from the Sun.
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Pi Canis Majoris (π Canis Majoris) is a binary star system in the southern constellation of Canis Major. It is visible to the naked eye, having an apparent visual magnitude of +4.69. Based upon an annual parallax shift of 33.80 mas as seen from Earth, this system is located 96.5 light years from the Sun. The star is moving in the general direction of the Sun with a radial velocity of −37.9 km/s.
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Xi Coronae Borealis (ξ CrB) is a binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of 4.85. Based upon an annual parallax shift of 17.78 mas as seen from the Earth, it is located about 183 light years from the Sun. As of 2009, the pair had an angular separation of 91 mas along a position angle of 139.4°.
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Gamma Coronae Borealis, Latinized from γ Coronae Borealis, is a binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with an apparent visual magnitude of 3.83. Based upon an annual parallax shift of 22.33 mas as seen from Earth, it is located about 146 light years from the Sun. The system is moving closer to the Sun with a radial velocity of about −15 km/s.
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HD 216446 is a binary star system in the northern circumpolar constellation of Cepheus. It is faintly visible to the naked eye with a combined apparent visual magnitude of 4.77. The system is located at a distance of approximately 319 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −32 km/s. It is predicted to come to within in around 1.876 million years.
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12 Comae Berenices is a binary star system in the northern constellation of Coma Berenices. It is the brightest member of the Coma Cluster and is visible to the naked eye with an apparent visual magnitude of 4.80. Although listed as a suspected variable star, there is no photometric evidence of it being variable in luminosity. However, the radial velocity was found to be variable, as announced by W. W. Campbell in 1910.
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HD 106760 is a single-lined spectroscopic binary star system in the northern constellation of Coma Berenices. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.99. The system is located around 38 light years away, as determined from its annual parallax shift of . It is moving closer with a heliocentric radial velocity of −40 km/s, and is expected to come as close as in about 772,000 years.
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Alpha Tucanae (α Tuc, α Tucanae) is a binary star system in the southern circumpolar constellation of Tucana. With an apparent visual magnitude of 2.86, it can be seen with the naked eye from the southern hemisphere. Using parallax measurements, the distance to this system can be estimated as . A cool star with a surface temperature of 4300 K, it is 424 times as luminous as the sun and 37 times its diameter.
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KIC 9832227 is a contact binary star system in the constellation Cygnus, located about 1,940 ± 30 light-years away. It is also identified as an eclipsing binary with an orbital period of almost 11 hours. In 2017, the system was predicted to result in a merger in 2022.2 (± 0.6 years), producing a luminous red nova (LRN) reaching an apparent magnitude of 2. The LRN would remain visible to the naked eye for roughly a month.
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Iota Trianguli Australis (ι Trianguli Australis) is a binary star system in the constellation Triangulum Australe. It is visible to the naked eye with a combined apparent visual magnitude of +5.27. Based upon an annual parallax shift of 25.77 mas as seen from the Earth, it is located around 127 light years from the Sun. The system appears to be moving closer to the Sun with a radial velocity of around −6 km/s.
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HD 222109 is a binary star system in the northern constellation of Andromeda. They have a combined apparent visual magnitude of 5.80, making them visible by the naked eye as a single star. They also have a combined spectral classification B8V. The pair is located at approximately 800 light years from Solar System, and orbit each other with a period of 351.22 years, a separation of 0.41″, and an orbital eccentricity of 0.39.
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ET Andromedae is a binary star system star in the northern constellation of Andromeda. It has an apparent visual magnitude of 6.48, placing it at the nominal limit for visibility with the naked eye. The distance to this system can be estimated from its annual parallax shift of , which yields a value of 602 light years. Variations in the radial velocity of this star suggest it is a single-lined spectroscopic binary system.
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HD 6114 is a visual binary star system in the northern constellation of Andromeda. With a combined apparent magnitude of 6.46, the star can only be seen with the naked eye by keen-eyed observers even on the best of nights. Based upon an annual parallax shift of as seen from Earth's orbit, the system is located approximately distant. The binary nature of this system was discovered by O. Struve in 1864.
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22 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis, located 212 light years away from the Sun. It has an apparent visual magnitude of 7.03, which is below the normal limit for visibility with the naked eye. This object is moving further from the Earth with a mean heliocentric radial velocity of +10 km/s. Eggen (1991) listed it as a member of the IC 2391 supercluster.
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Beta1 Sagittarii, Latinized from β1 Sagittarii, is a binary star system in the zodiac constellation of Sagittarius, next to the southern constellation border with Telescopium. The brighter primary is named Arkab Prior , the traditional name of the system. It is visible to the naked eye with a combined apparent visual magnitude of +4.01. Based upon an annual parallax shift of 10.40 mas as seen from Earth, it is located roughly 310 light-years from the Sun.
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Alpha Volantis (α Vol, α Volantis) is a binary star system in the southern constellation Volans. It has an apparent visual magnitude of +4.00, which is bright enough to be seen with the naked eye. Based upon parallax measurements made with the Hipparcos spacecraft, it is located at a distance of 125 light years from the Sun. As of 2010, the two components of this system had an angular separation of 0.0318″ along a position angle of 286.9°.
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Omega Piscium (Omega Psc, ω Piscium, ω Psc) is a star approximately 106 light years away from Earth, in the constellation Pisces. It has a spectral type of F4IV, meaning it is a subgiant/dwarf star, and it has a temperature of 6,600 kelvins. It may or may not be a close binary star system. Variations in its spectrum were once interpreted as giving it an orbital period of 2.16 days, but this claim was later debunked as false.
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HD 59686 is a binary star system in the northern constellation of Gemini. It is visible to the naked eye as a dim point of light with an apparent visual magnitude of +5.45. The distance to this system is approximately 292 light years based on parallax, but it is drifting closer with a radial velocity of −34 km/s. This is a single-lined spectroscopic binary system with an orbital period of and a high eccentricity of 0.73.
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Pi1 Ursae Minoris is a common proper motion binary star system in the northern circumpolar constellation of Ursa Minor. The pair have apparent visual magnitudes of +6.58 and +7.31, with a combined magnitude of 6.1. They are located about 71 light years from the Sun. The two have an angular separation of 31.4 arc seconds, which corresponds to a physical separation of about 680 AU, and orbit each other with a period of about 13,100 years.
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Pi2 Ursae Minoris (π2 UMi) is a binary star system in the northern circumpolar constellation of Ursa Minor. The pair have apparent magnitudes of 7.32 and 8.15, placing them below the brightness limit of stars that can be readily viewed with the naked eye. They are located about 390 light-years (120 parsecs) away from the Sun. The two have an angular separation of 0.464″ on average, and they orbit each other with a period of about 170 years.
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40 Persei is a wide binary star system in the northern constellation of Perseus. It has the Bayer designation ο Persei, while 40 Persei is the Flamsteed designation. The system is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude of 4.97. It is located approximately 1060 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +22 km/s.
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Gallifrey () is a fictional planet in the long-running British science fiction television series Doctor Who. It is the original home world of the Time Lords, the civilisation to which the main protagonist, the Doctor belongs. It is located in a binary star system 250 million light years from Earth. It was first shown in The War Games (1969) during the Second Doctor's trial though was not identified by name until The Time Warrior (1973–74).
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The constellation of Reticulum, the net, as it can be seen by the naked eye Only two of the stars in this constellation are brighter than visual magnitude 5: Alpha (α) and Beta (β) reticuli. The reddish star R Reticuli is a Mira variable. This variable was discovered by C. Ragoonatha Chary at the Madras Observatory in India. The binary star system Epsilon Reticuli consists of a spectral class K2IV star being orbited by a white dwarf.
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Based on parallax measurements, this system is located about 50 light years from the Sun. In 2000, a planetary companion was announced, orbiting the star ε Reticuli A. Zeta Reticuli is a wide binary star system, with both members being similar to the Sun. It is located at a distance of about 39 light years. This system gained some notoriety in ufology when the alleged alien abductees Betty and Barney Hill named it as the home of their abductors.
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This name was later connected by Allen with 46 Leonis Minoris—an error perpetuated by subsequent astronomers. The original "Praecipua", 37 Leonis Minoris, has an apparent magnitude of 4.69, but is a distant yellow supergiant of spectral type G2.5IIa and absolute magnitude of −1.84, around distant. Leo Minor as seen by the naked eye Beta Leonis Minoris is a binary star system. The primary is a giant star of spectral class G8 and apparent magnitude of 4.4.
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HD 111597 is a suspected astrometric binary star system in the southern constellation of Centaurus. It has the Bayer designation p Centauri, while HD 111597 is the star's identifier from the Henry Draper catalogue. The system is visible to the naked eye as a faint point of light with an apparent visual magnitude of 4.90. It is located at a distance of approximately 380 light years from the Sun based on parallax, and has an absolute magnitude of −0.53.
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These types of stars are a few times more massive than the Sun, and have effective temperatures of about 10,000 to 30,000 K. x1 Centauri is just over 3 times more massive than the Sun and has a temperature of about 11,300 K. The star x2 Centauri, which lies about 0.4′ away from x1 Centauri, may or may not form a physical binary star system with x1 Centauri, as the two have similar proper motions and distances.
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Nu Piscium (ν Piscium) is an orange-hued binary star system in the zodiac constellation of Pisces. Prior to the formation of the modern constellation boundaries in 1930, it was designated 51 Ceti in the Cetus constellation. Nu Piscium is visible to the naked eye, having a combined apparent visual magnitude of 4.44. Based upon an annual parallax shift of 8.98 mas as seen from Earth, it is located about 363 light years from the Sun.
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78 Pegasi is a binary star system in the northern constellation of Pegasus. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.93. The system is located approximately 224 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −8 km/s. The double-star nature of this system was discovered by A. G. Clark in 1862.
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17 Cygni is the Flamsteed designation for a binary star system in the northern constellation of Cygnus. It has an apparent visual magnitude of 5.00, so, according to the Bortle scale, it is visible from suburban skies at night. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.0478″, which is equivalent to a distance of around from the Sun. It has a relatively high proper motion, traversing the celestial sphere at the rate of /year.
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Delta Pyxidis (δ Pyxidis) is binary star system in southern constellation of Pyxis. Having an apparent visual magnitude of +4.877, it is bright enough to be visible to the naked eye. Based upon an annual parallax shift of 13.19 mas as seen from Earth, it is located around 250 light years from the Sun. In Chinese, (), meaning Celestial Dog, refers to an asterism consisting of δ Pyxidis, e Velorum, f Velorum, β Pyxidis, α Pyxidis and γ Pyxidis.
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Tau Draconis, Latinized from τ Draconis, is an astrometric binary star system in the northern circumpolar constellation of Draco. The star is faintly visible to the naked eye, having an apparent visual magnitude of 4.45. Based upon an annual parallax shift of 22.28 mas as measured from Earth, it is located around 146 light years from the Sun. Its proper motion is propelling it across the sky at the rate of 0.176 arc seconds per year.
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Kepler-453b is a transiting circumbinary exoplanet in the binary-star system Kepler-453. It orbits the binary system in the habitable zone every 240.5 days. The orbit of the planet is inclined relative to the binary orbit therefore precession of the orbit leads to it spending most of its time in a non-transiting configuration. By the time the TESS and PLATO spacecraft are available for follow up observations it will no longer be transiting.
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HY Velorum is a binary star system in the southern constellation of Vela. It is a dim star but visible to the naked eye with an apparent visual magnitude of 4.83. The distance to this system, as estimated from its annual parallax shift of , is 460 light years. HY Vel most likely forms a gravitationally bound pair with the magnitude 5.45 binary system KT Vel (HD 74535); both are members of the IC 2391 open cluster.
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Theta Piscis Austrini (θ Piscis Austrini) is a binary star system in the southern constellation of Piscis Austrinus. It is faintly visible to the naked eye with a combined apparent visual magnitude of +5.01. Based upon an annual parallax shift of 10.16 mas as seen from the Earth, the system is located around 320 light years from the Sun. The binary nature of this system was discovered in 1951 by South African astronomer W. S. Finsen.
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The component k1 Puppis is a binary star system in its own right, while k2 Puppis is a variable star. Each star within the k Puppis optical pair is between 450 and 470 light years from Earth. k Puppis is listed in the General Catalogue of Variable Stars as a suspected variable star, but the range and type are not stated. The International Bulletin of Variable Stars has since published research showing that k2 Puppis is the variable component.
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Eta Delphini, Latinized from η Delphini, is a candidate astrometric binary star system in the northern constellation of Delphinus. It has an apparent magnitude of about 5.4, meaning that it is faintly visible to the naked eye. Based upon a parallax measurement of 13.81 mas made by the Hipparcos spacecraft, this star is around 240 light years away from the Sun. It is advancing in general direction of the Earth with a radial velocity of −25 km/s.
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WW Aurigae is an eclipsing binary star system in the northern constellation of Auriga. It has a combined maximum apparent visual magnitude of 5.86, which is bright enough to be dimly visible to the naked eye. Based upon an annual parallax shift of , it is located 297 light years from the Earth. The system is moving further away with a heliocentric radial velocity of −9 km/s, having come to within some 3.12 million years ago.
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Omega Cassiopeiae (ω Cassiopeiae) is a binary star system in the northern constellation of Cassiopeia. It has a combined apparent visual magnitude of +4.99, which means it is a faint star but visible to the naked eye. Based upon an annual parallax shift of 4.65 mas as seen from Earth, this system is located roughly 700 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.16 due to interstellar dust.
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29 Aquarii is a binary star system located around 590 light years away from the Sun in the equatorial constellation of Aquarius. 29 Aquarii is the Flamsteed designation; the system also bears the variable star designation DX Aquarii. It is a challenge to view with the naked eye, appearing as a dim star with a combined apparent visual magnitude of 6.39. The system is moving further from the Earth with a heliocentric radial velocity of about +15 km/s.
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45 Aurigae or PLX 1468.2 is a binary star system in the northern constellation of Auriga. It has an apparent visual magnitude of 5.34, making it visible to the naked eye under suitable viewing conditions. An annual parallax shift of 16.89 mas as seen from Earth's orbit indicates the system is located about 193 light years from the Sun. This is a close, single-lined spectroscopic binary with a circularized orbit with a short period of 6.5 days.
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39 Cygni is a binary star system near the southern border of the northern constellation of Cygnus, approximately 250 light years away from Earth. It is visible to the naked eye as an orange-hued star with an apparent visual magnitude of 4.43. The system is moving closer to the Sun with a heliocentric radial velocity of −17 km/s. This is a single-lined spectroscopic binary with an orbital period of about and an eccentricity of 0.5.
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10 Boötis is a suspected astrometric binary star system in the northern constellation of Boötes, located around 528 light years away from the Sun. It is visible to the naked eye under suitable viewing conditions as a dim, white- hued star with an apparent visual magnitude of 5.76. Its magnitude is diminished by an extinction of 0.17 due to interstellar dust. This system is moving away from the Earth with a heliocentric radial velocity of +6 km/s.
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15 Boötis is a binary star system in the northern constellation of Boötes, located approximately 260 light years away from the Sun. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.45. The system has a relatively high proper motion, traversing the celestial sphere at the rate of 0.166 arc seconds per annum. It is moving away from the Earth with a heliocentric radial velocity of +16.8 km/s.
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This is a single-lined spectroscopic binary star system with an orbital period of 207.357 days and an eccentricity of 0.55. The primary component has the spectrum of an evolved F-type giant/bright giant hybrid with a stellar classification of F7 II/III. It is around 46 million years old with 6.9 times the mass of the Sun. The star is radiating 3,919 times the Sun's luminosity from its photosphere at an effective temperature of 6,495 K.
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Chi Geminorum (χ Gem) is a binary star system in the constellation Gemini, near the western border with Cancer. It can be viewed with the naked eye on a dark night, having an apparent visual magnitude of 4.98. Based upon an annual parallax shift of 12.73 mas, it is located roughly 260 light years from the Sun. The two components of this system form a spectroscopic binary with an orbital period of 2,437.8 days and an eccentricity of 0.06.
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Sigma Aquilae, Latinized from σ Aquilae, is the Bayer designation for a binary star system in the equatorial constellation of Aquila. The baseline apparent magnitude of the pair is +5.17, which, according to the Bortle Dark-Sky Scale, is bright enough to be seen with the naked eye from suburban skies. Because of the Earth's orbit about the Sun, this system has an annual parallax shift of 4.18 mas. This provides a distance estimate of approximately .
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Xi Arietis, Latinized from ξ Arietis, is the Bayer designation for a binary star system in the northern constellation of Aries. It has an apparent visual magnitude of 5.46, and so is dimly visible to the naked eye. Based upon an annual parallax shift of as seen from Earth, it is distant from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.24 due to interstellar dust.
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23 Ursae Majoris, or 23 UMa, is a binary star system in the constellation Ursa Major, located is approximately 77.7 light years from the Sun. It has the Bayer designation h Ursae Majoris; 23 Ursae Majoris is the Flamsteed designation. The system is visible to the naked eye as a yellow-white hued star with an apparent visual magnitude of +3.65. It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.
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HR 3643 is a binary star system in the southern constellation of Carina. It has the Bayer designation G Carinae, with HR 3643 being the star's designation in the Bright Star Catalogue. The system is visible to the naked eye with an apparent visual magnitude of 4.48. It is located at a distance of approximately 401 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +22.5 km/s.
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Delta1 Gruis, Latinized from δ1 Gruis, is a candidate binary star system in the constellation Grus. With a peak apparent visual magnitude of 3.97, it is bright enough to be seen with the naked eye at night. The distance to this system, as determined using an annual parallax shift of 10.54 mas as seen from the Earth, is around 309 light years. It is gradually moving away from the Sun with a radial velocity of +4.9 km/s.
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HD 34790 is a double-lined spectroscopic binary star system in the northern constellation of Auriga. It has a combined apparent magnitude of 5.66, which means it is faintly visible to the naked eye. Based upon observations by the Hipparcos satellite, it is located around 289 light years away. It has a combined stellar classification of A1Vs, matching that of an A-type main sequence star, and shines with 35 times the luminosity of the Sun.
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It forms a triangle with the fainter φ1 Hydrae and φ2 Hydrae, between μ Hydrae and ν Hydrae. This is a single-lined spectroscopic binary star system with an orbital period of about 1,200 days and an eccentricity of 0.1. The primary, component A, is an evolved G-type giant star with a stellar classification of G8 III. It is a red clump star, which means it is generating energy through the fusion of helium at its core.
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Kappa Cephei, Latinized from κ Cephei, is a binary star system in the northern circumpolar constellation of Cepheus. It is visible to the naked eye as a faint, blue white-hued point of light with an apparent visual magnitude is 4.39. The system is located approximately 323–326 light years distant from the Sun, based on parallax. The two gravitationally-bound members of this system had an angular separation of along a position angle of 120°, as of 2015.
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In astronomy, Gaia16aye is a gravitational microlensing event of the star 2MASS 19400112+3007533 (the source star) by a dimmer binary star system (the lens star system). The source star 2MASS 19400112+3007533 is a magnitude 14.5 (Gaia RP) star in Cygnus. It was closely observed during a set of brightening events caused by gravitational microlensing in 2016. The Gaia16aye event was first noticed by the Gaia space mission via an alert on August 9, 2016.
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CE Gruis (previously called Grus V-1) is a faint binary star system in the constellation Grus. Its brightness changes between magnitudes 17.4 and 19.5 with a period of 108.6 minutes. It is composed of a white dwarf and donor star, locked into a synchronous orbit. In such systems, known as polars, material from the donor star does not form an accretion disc around the white dwarf because of its intense magnetic field, but rather streams directly onto it.
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Delta Muscae, Latinized from δ Muscae, often catalogued as HD 112985, is a spectroscopic binary star system and the closest to the Earth in the southern hemisphere constellation of Musca (the Fly) at a distance of approximately 27.8 parsecs (91.0 light years). The main star is classified as a giant star with an orange tint. It is one of the stars given a Bayer designation by astronomer Johann Bayer. It was recorded in Bayer's 1603 publication Uranometria.
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32 Cygni 32 Cygni (32 Cyg, Omicron2 Cyg, ο2 Cyg) is the Flamsteed designation for a binary star system in the Cygnus constellation. It is a 4th magnitude star, which can be seen with the naked eye under suitably dark skies. Parallax measurements give an estimated distance of 1,100 light-years (320 parsecs) from the Earth. However, Schröder et al. (2007) suggest the actual value, after correcting for Malmquist bias, may be closer to 1,174 light-years (360 parsecs).
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This is an Algol-like eclipsing binary star system, with a period of 2.3274 days and an eccentricity of 0.07. Its apparent magnitude varies from 4.91m to 5.9m. The secondary is filling its roche lobe and there is evidence of large-scale mass transfer in the past, with the star being more evolved than the primary. Along with λ Tau, it was one of the first stars on which rotational line broadening was observed, by Frank Schlesinger in 1911.
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HD 212301 is a binary star system in the south circumpolar constellation of Octans. This star is also called HIP 110852. With an apparent visual magnitude of 7.76, it is too faint to be visible to the naked eye. The system is located at a distance of 177 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +4.7 km/s. It has an absolute magnitude of 4.06.
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MY Camelopardalis (MY Cam) is a binary star system located in the Alicante 1 open cluster, some away in the constellation Camelopardalis. It is one of the most massive known binary star systems and a leading candidate for a massive star merger. MY Cam is the brightest star in Alicante 1. The system consists of two hot blue O-type stars with one component having a mass of 32 solar masses and the other 38 solar masses.
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The constellation Virgo as it appears in the manga. The series is named after Spica, a binary star system in the constellation Virgo and one of the brightest stars in the nighttime sky. It appears as one star because of the relatively low center-to-center distance between the two component stars, estimated at an average of 11 million miles (17.7 million km). Astronomical observations also suggest that there may be additional stars in the Spica system.
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HD 134687 (e Lupi) is a binary star system in the southern constellation Lupus. It is visible to the naked eye with an apparent visual magnitude of 4.81. The distance to HD 134687 can be estimated from its annual parallax shift of , yielding a separation of roughly 730 light years. It is a member of the ~11 million year old Upper Centaurus Lupus subgroup of the Scorpius–Centaurus Association, the closest OB association to the Sun.
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Omega Herculis (ω Herculis, abbreviated Ome Her, ω Her) is a binary star system in the northern constellation of Hercules. Based upon an annual parallax shift of 13.04 mas as seen from Earth, it is located around 250 light-years from the Sun. It is faintly visible to the naked eye, having a combined apparent visual magnitude of 4.58. The system is a candidate for membership in the Ursa Major Moving Group, although this remains uncertain.
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Delta Cassiopeiae (δ Cassiopeiae, abbreviated Delta Cas, δ Cas) is an eclipsing binary star system in the northern circumpolar constellation of Cassiopeia. Based on parallax measurements taken during the Hipparcos mission, it is approximately from the Earth. Delta Cassiopeiae is the primary or 'A' component of a multiple star system designated WDS J01258+6014. Delta Cassiopeiae's two components are therefore designated WDS J01258+6014 Aa and Ab. Aa is officially named Ruchbah , the traditional name for the system.
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This is a spectroscopic binary star system with components that orbit each other every 3848.8 days (10.5 years). The combined stellar classification of the system is K0.5 IIIb, which matches the spectrum of a normal luminosity giant star. It has an apparent visual magnitude of 2.4, so it is somewhat outshined by its first magnitude neighbors Achernar (α Eridani) and Fomalhaut (α Piscis Australis). Based upon parallax measurements, this system is at a distance of about from the Earth.
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HD 177830 is a 7th magnitude binary star system located approximately 205 light-years away in the constellation of Lyra. The primary star is slightly more massive than our Sun, but cooler being a type K star. Therefore, it is a subgiant clearly more evolved than the Sun. In visual light it is four times brighter than the Sun, but because of its distance, about 205 light years, it is not visible to the unaided eye.
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QS Telescopii is a faint binary star system in the constellation Telescopium. It is composed of a white dwarf and main sequence donor star, in this case the two are so close and fused into orbit facing one another. Known as polars, material from the donor star does not form an accretion disk around the white dwarf, but rather streams directly onto it. This is due to the presence of the white dwarf's strong magnetic field.
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HD 91190 is a suspected astrometric binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.86. The distance to HD 91190, as estimated from its annual parallax shift of , is around 720 light years. This system is moving further away from the Sun with a heliocentric radial velocity of +17 km/s, having come to within some 2.4 million years ago.
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6 Draconis is a single-lined spectroscopic binary star system in the northern constellation of Draco, located about 430 light years away from the Sun. It is visible to the naked eye as an orange-hued star with an apparent visual magnitude of 4.95. The system is moving further from the Earth with a heliocentric radial velocity of 3 km/s. The variable radial velocity of this star system was announced by W. W. Campbell in 1922.
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27 Canis Majoris is a binary star system in the northern constellation of Canis Major, located approximately 1,700 light years away from the Sun. It has the variable star designation EW Canis Majoris; 27 Canis Majoris is the Flamsteed designation. This system is visible to the naked eye as a dim, blue- white hued star with an apparent visual magnitude of +4.65. It is moving away from the Earth with a heliocentric radial velocity of 16 km/s.
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This spectroscopic binary star system has an orbital period of 389.31 days, a semimajor axis of 1.48 AU, and an eccentricity of 0.2586. Their variable radial velocity was discovered by H. M. Reese in 1902 at Lick Observatory. Both components are evolved, K-type giant stars, most likely on their first ascent along the red giant branch. The primary, component A, has a stellar classification of K4 III while the secondary, component B, may be K1: III.
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Tau Coronae Borealis, Latinized from τ Coronae Borealis, is a possible astrometric and spectroscopic binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with an apparent visual magnitude of 4.76. Tau CrB has a visible companion of visual magnitude 13.2 and they have been treated as a common proper motion pair. As of 2014, the pair had an angular separation of 2.20 arc seconds along a position angle of 186°.
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Iota Coronae Borealis, Latinized from ι Coronae Borealis, is a binary star system in the constellation Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of is 4.96. Based upon an annual parallax shift of 10.46 mas as seen from the Earth, it is located about 312 light years from the Sun. This is a single-lined spectroscopic binary with an orbital period of 35.5 days and an eccentricity of 0.56.
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Theta Coronae Borealis, Latinized from θ Coronae Borealis, is a binary star system in the constellation Corona Borealis. It shines with a combined apparent visual magnitude (V band) of 4.13. There are two components: Theta Coronae Borealis A is of apparent magnitude 4.16, while Theta Coronae Borealis B lies around 1 arcsecond distant and has an apparent magnitude of 6.29. The system is located around 375 light-years from Earth, as estimated from its parallax of 8.69 milliarcseconds.
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Kappa1 Sculptoris is a binary star system in the southern constellation of Sculptor. It is faintly visible to the naked eye, with a combined apparent visual magnitude of +5.51. Based upon an annual parallax shift of 12.91 mas as measured from Earth, it is located roughly 250 light years from the Sun. The pair orbit each other with an estimated period of 616 years, a semimajor axis of 1.5 arc seconds, and an eccentricity of 0.1.
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23 Comae Berenices is a binary star system in the northern constellation of Coma Berenices, situated a few degrees away from the North Galactic Pole. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.80. The system is located around 310 light years away from the Sun, based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.
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Upsilon Lupi, Latinized from υ Lupi, is a star system in the southern constellation of Lupus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.37. Based upon an annual parallax shift of 8.02 mas as seen from Earth, it is located around 410 light years from the Sun. The two components of Upsilon Lupi share a common proper motion through space and most likely form a wide binary star system.
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Rho Tucanae (ρ Tuc, ρ Tucanae) is a binary star system in the southern constellation of Tucana. It is visible to the naked eye with a combined apparent visual magnitude of +5.38. Based upon an annual parallax shift of 24.37 mas as seen from Earth, it is located 131 light years from the Sun. This is a single-lined spectroscopic binary with a close, nearly circular orbit having a period of 4.82 days and an eccentricity of 0.02.
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Zeta Horologii, Latinized from ζ Horologii, is a yellow-white hued binary star system in the southern constellation of Horologium. It is visible to the naked eye with a combined apparent visual magnitude of 5.20. Based upon an annual parallax shift of 20.37 mas as seen from Earth, it is located around 160 light years from the Sun. This system was determined to be a double-lined spectroscopic binary by J. H. Moore in 1911−12.
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HD 80606 and HD 80607 are two stars comprising a binary star system. They are approximately 217 light-years away in the constellation of Ursa Major. Both stars orbit each other at an average distance of 1,200 astronomical units. The binary system is listed as Σ1341 in the Struve Catalogue of Double Stars, however this designation is not in wide use and the system is usually referred to by the HD designations of its constituent stars.
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HR 6384 is a binary star system in the southern constellation of Ara, the Altar. The system is faintly visible to the naked eye with a combined apparent visual magnitude that fluctuates around 6.153, and it is located at a distance of approximately from the Sun. It is drifting closer with a radial velocity of around −34 km/s. The system appears to be a close, interacting binary with a hot secondary component of class A or hotter.
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Chandra observations have also revealed a point source at the position of the central star. The spectrum of this source extends to the hard part of the X-ray spectrum, to 0.5–. A star with the photospheric temperature of about would not be expected to emit strongly in hard X-rays, and so their presence is something of a mystery. It may suggest the presence of a high temperature accretion disk within a binary star system.
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Gamma Camelopardalis, Latinized from γ Camelopardalis, is a suspected wide binary star system in the northern circumpolar constellation of Camelopardalis. With a visual magnitude of 4.66, it is faintly visible to the naked eye. Based upon an annual parallax shift of 9.09 mas as seen from Earth, this star is located about 359 light years from the Sun. The brighter primary, designated component A, is a white-hued A-type subgiant star with a stellar classification of A2 IVn.
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Omega Sagittarii, which is Latinized from ω Sagittarii, is a binary star system in the constellation of Sagittarius, near the eastern constellation border with Capricornus. It is formally named Terebellum . This system has a yellow hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.70. It is located at a distance of 76 light years away from the Sun based on parallax, and is drifting closer with a radial velocity of −16 km/s.
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2 Persei is a binary star system in the northern constellation Perseus, located around 500 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude is 5.70. The system is moving further away from the Earth with a heliocentric radial velocity of 11 km/s. In 1970 radial velocity measurements from spectrograms taken at David Dunlap Observatory indicated it was a single-lined spectroscopic binary.
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Xi Orionis (ξ Orionis) is a binary star system in the northeastern part of the constellation of Orion, well above the red giant star, Betelgeuse in the sky. It lies next to another blue main-sequence star, Nu Orionis which is somewhat closer at 520 light years. The apparent visual magnitude of Xi Orionis is 4.47, which is bright enough to be seen with the naked eye. The distance to this star, as determined using the parallax method, is roughly 610 light years.
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Mu Velorum (μ Vel, μ Velorum) is a binary star system in the southern constellation Vela. The two stars orbit each other with a semi-major axis of 1.437 arcseconds and a period of 116.24 years. (Wulff-Dieter Heintz (1986) lists a period of 138 years with his orbital elements.) The pair have a combined apparent visual magnitude of 2.69, making the system readily visible to the naked eye. From parallax measurements, the distance to this system is estimated to be .
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HR 4072 is a binary star system in the northern circumpolar constellation of Ursa Major. It has the variable star designation ET Ursae Majoris, abbreviated ET Uma, while HR 4072 is the system's designation from the Bright Star Catalogue. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.94. The system is located at a distance of approximately 339 light years from the Sun based on parallax measurements.
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It is around five times as massive as our Sun. Beta Muscae is a binary star system around 341 light-years distant that is composed of two blue-white main-sequence stars of spectral types B2V and B3V that orbit each other every 194 years. They are eight and six times as massive as the Sun, respectively, and have about 3.5 times its diameter. Zeta2 Muscae is a white main sequence star of spectral type A5V around 330 light- years distant from Earth.
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Diagram of an intermediate polar. Matter flows from the companion star into an accretion disk around the white dwarf, but is disrupted by the white dwarf's magnetic field. An Intermediate Polar (also called a DQ Herculis Star) is a type of cataclysmic variable binary star system with a white dwarf and a cool main-sequence secondary star. In most cataclysmic variables, matter from the companion star is gravitationally stripped by the compact star and forms an accretion disk around it.
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Eta1 Coronae Australis, Latinized from η1 CrA, is a suspected astrometric binary star system in the constellation of Corona Australis. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.456. Parallax measurements put it at a distance of 317 light- years away from the Sun. The visible component is an A-type main-sequence star with a stellar classification of A3V, which indicates it is generating energy through core hydrogen fusion.
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72 Pegasi is a binary star system in the northern constellation of Pegasus. It is visible to the naked eye as a faint, orange-hued point of light with a combined apparent visual magnitude of 4.97. The system is located approximately 550 light years away from the Sun, based on parallax, but is drifting closer with a radial velocity of −25 km/s. This is a visual binary with an orbital period of roughly 492 years and an eccentricity of 0.32.
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Omega Ursae Majoris (Omega UMa, ω Ursae Majoris, ω UMa) is the Bayer designation for a binary star system in the northern circumpolar constellation of Ursa Major. It is visible to the naked eye with an apparent visual magnitude of 4.61. Based upon an annual parallax shift of 13.24 mas, it is roughly 246 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.11 due to interstellar dust.
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19 Puppis is a binary star system in the southern constellation of Puppis, near the northern border with Hydra and Monoceros. It is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.72. The system is located approximately 177 light years away from the system based on parallax. It is receding from the Earth with a heliocentric radial velocity of +36 km/s, having come to within some 1.4 million years ago.
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HD 2638 is a binary star system in the equatorial constellation of Cetus. The pair have an angular separation of along a position angle of 166.7°, as of 2015. This is system too faint to be visible to the naked eye, having a combined apparent visual magnitude of 9.44; a small telescope is required. The distance to this system is 179.5 light years based on parallax, and it is drifting further away with a radial velocity of +9.6 km/s.
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This is a single-lined spectroscopic binary star system with an orbital period of 36.5 days and an eccentricity of roughly 0.3. The visible component is a B-type main-sequence star with a stellar classification of B7 V. It is spinning rapidly with a projected rotational velocity of 212 km/s. The star has 4.2 times the mass of the Sun and is radiating around 611 times the Sun's luminosity from its photosphere at an effective temperature of 9,908 K.
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4 Equulei is a binary star system in the constellation of Equuleus, located about 3° to the east of Alpha Equulei. With an apparent visual magnitude of 5.94, it is just barely visible to the naked eye under good seeing conditions. The system shows an annual parallax shift of 20.44 mas as measured from Earth's orbit, which yields a distance estimate of about 160 light years. It is moving closer to the Sun with a radial velocity of −13 km/s.
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HR 4796 is a binary star system in the southern constellation of Centaurus. Parallax measurements put it at a distance of from the Earth. The two components of this system have an angular separation of 7.7 arcseconds, which, at their estimated distance, is equivalent to a projected separation of about 560 Astronomical Units (AU), or 560 times the separation of the Earth from the Sun. The star and its ring resemble an eye, and it is sometimes known by the nickname "Sauron's Eye".
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V1472 Aquilae is a semi-regular pulsating star in the constellation Aquila. It is actually a binary star system, the main component being a red giant of spectral type M2.5 III. Original calculations using hipparcos data gave a parallax of 7.92 ± 1.07 milliarcseconds, but reprocessing to allow for orbital motion adjusts the parallax to 2.4 ± 1.0 milliarcseconds—tripling the system's distance from Earth. The main star has a diameter 104 ± 56 times and luminosity 1100 times that of the Sun.
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18 Vulpeculae is a binary star system in the northern constellation of Vulpecula, located about 489 light years away from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.51. The system is moving closer to the Earth with a heliocentric radial velocity of −11.7 km/s. This is a double-lined spectroscopic binary system with an orbital period of 9.3 days and a small eccentricity of 0.0116.
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Nu Cygni, Latinized from ν Cygni, is a binary star system in the constellation Cygnus. Its apparent magnitude is 3.94 and it is approximately 374 light years away based on parallax. The brighter component is a magnitude 4.07 A-type giant star with a stellar classification of A0III n, where the 'n' indicates broad "nebulous" absorption lines due to rapid rotation. This white-hued star has an estimated 3.6 times the mass of the Sun and about 1.9 times the Sun's radius.
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41 Ophiuchi is a binary star system in the zodiac constellation of Ophiuchus, and is positioned less than half a degree to the south of the celestial equator. It is visible to the naked eye as a faint, orange-hued point of light with a combined apparent visual magnitude of 4.72. The distance to this system is approximately 202 light years based on parallax. This is a visual binary with an orbital period of 141 years and an eccentricity of 0.866.
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HD 1237 is a binary star system approximately 57 light-years away in the constellation of Hydrus (the Water Snake). The visible star in the system, A, is considered to be a solar analog due close mass to the sun. HD 1237 differs from the sun in that HD 1237 is much younger, has high metallicity, has much cooler temperature and is in a binary system. As of 2000, it has been confirmed that an extrasolar planet orbits the star.
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54 Aurigae is a binary star system located around 800 light years away from the Sun in the northern constellation of Auriga. It is visible to the naked eye as a dim, blue-white hued star with a combined apparent visual magnitude of 6.02. The system is moving further from the Sun with a heliocentric radial velocity of around +19 km/s. The primary component is a B-type giant star of visual magnitude 6.22 with a stellar classification of B7 III.
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4 Cassiopeiae is a wide binary star system in the northern constellation of Cassiopeia, located approximately 790 light-years away from the Sun. It is visible to the naked eye as a faint, red-hued star with a baseline apparent visual magnitude of 4.96. At the distance of this system, its visual magnitude is diminished by an extinction of 0.56 due to interstellar dust. This system is moving closer to the Earth with a heliocentric radial velocity of −39 km/s.
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65 Aurigae is a binary star system located 252 light years away from the Sun in the northern constellation of Auriga. It is visible to the naked eye as a faint, orange hued star with an apparent visual magnitude of 5.12. The primary, designated component A, is an aging giant star with a stellar classification of K0 III. It is 3.31 billion years old and has expanded to 13 times the Sun's radius after exhausting the hydrogen at its core.
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53 Aquarii (abbreviated 53 Aqr) is a binary star system in the equatorial constellation of Aquarius. 53 Aquarii is its Flamsteed designation though the star also bears the Bayer designation of f Aquarii. The combined apparent visual magnitude of the pair is a 5.56, making it just visible to the naked eye in dark suburban skies. Based upon an annual parallax shift of 49.50 milliarcseconds for the first component, this system is located at a distance of approximately from Earth.
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14 Boötis is a possible binary star system located 110 light years away from the Sun in the northern constellation of Boötes. It is visible to the naked eye as a dim, yellow-white hued star with a combined apparent visual magnitude of 5.53. This system is moving closer to the Earth with a heliocentric radial velocity of −40 km/s. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.260 arc seconds per annum.
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Xi Cassiopeiae (ξ Cassiopeiae) is a blue-white hued binary star system in the northern constellation of Cassiopeia. It has an apparent visual magnitude of +4.81 and thus is faintly visible to the naked eye. Based upon an annual parallax shift of 2.28 mas as seen from Earth, this system is located roughly 1,400 light years from the Sun. At that distance, the visual magnitude of the system is diminished by an extinction factor of 0.20 due to interstellar dust.
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Nu Centauri (ν Cen, ν Centauri) is a binary star system in the southern constellation of Centaurus. The combined apparent visual magnitude of the pair is +3.41, making this one of the brightest members of the constellation. Based upon parallax measurements made during the Hipparcos mission, this star system is located at a distance of roughly from Earth. The margin of error for this distance is about 2%, which is enough to give an error in distance of ±10 light years.
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IK Pegasi (or HR 8210) is a binary star system in the constellation Pegasus. It is just luminous enough to be seen with the unaided eye, at a distance of about 154 light years from the Solar System. The primary (IK Pegasi A) is an A-type main-sequence star that displays minor pulsations in luminosity. It is categorized as a Delta Scuti variable star and it has a periodic cycle of luminosity variation that repeats itself about 22.9 times per day.
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31 Orionis is a binary star system in the equatorial constellation of Orion, located near the bright star Mintaka. It is visible to the naked eye as a faint, orange-hued point of light with a baseline apparent visual magnitude of 4.71. The distance to this system is approximately 490 light years away based on parallax, and it is drifting further away with a mean radial velocity of +6 km/s. As of 2008, the pair had an angular separation of .
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HD 189733, also catalogued as V452 Vulpeculae, is a binary star system approximately 64.5 light-years away in the constellation of Vulpecula (the Fox). The primary star is suspected to be an orange dwarf star, while the secondary star is a red dwarf star. Given that this system has the same visual magnitude as HD 209458, it promises much for the study of close transiting extrasolar planets. The star can be found with binoculars 0.3 degrees east of the Dumbbell Nebula (M27).
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When sufficient helium has accumulated along a shell on the surface of the white dwarf, a run-away thermonuclear explosion results in a nova outburst. Hence, V445 Puppis may belong to a binary star system and be surrounded by an accretion disk of matter drawn from the companion star. At present, the system is being obscured by an optically thick cloud of dust. A bi-polar outflow of material has been observed moving away from the system at a velocity of .
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18 Draconis is a likely binary star system in the northern circumpolar constellation of Draco. With an apparent visual magnitude of 4.84, it is just bright enough to be faintly visible to the naked eye. The distance to this system, as estimated from an annual parallax shift of , is roughly 720 light years. It is moving closer to the Sun with a heliocentric radial velocity of −1.4 km/s, and is a probable member of the Sirius stream of co-moving stars.
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SZ Crateris is a binary star system in the southern constellation Crater. Both components belong to the main sequence: the primary star has a spectral classification of K5V while the secondary is a red dwarf of spectral class M0V. The radius of the primary is about 66% the radius of the Sun, while the secondary member is only about 42% of the solar radius. In 1994, the two stars were separated by 5.1 arc seconds, which is equivalent to 112.41 astronomical units.
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15 Orionis is a suspected astrometric binary star system in the equatorial constellation of Orion, near the border with Taurus. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.82. The system is approximately 340 light years away from the Sun based on parallax. It is moving further from the Earth with a heliocentric radial velocity of +29 km/s, having come to within some three million years ago.
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Pi Aquilae, Latinized from π Aquilae, is the Bayer designation for a binary star system in the equatorial constellation of Aquila, about 3° to the north of the bright star Altair. The apparent visual magnitude of the system is 5.85, making it faintly visible to the naked eye from dark suburban skies. Based upon an annual parallax shift of 6.34 mas, the distance to this system is roughly . The binary nature of this system was first discovered by William Herschel in 1785.
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Delta Antliae (δ Ant, δ Antliae) is the Bayer designation for a binary star system in the southern constellation of Antlia. The combined apparent visual magnitude of the system is +5.57, allowing it to be viewed from the suburbs with the naked eye. Judging by the parallax shift of this system, it is located at a distance of 450 ± 10 light-years from Earth. The system is reduced in magnitude by 0.03 due to extinction caused by intervening gas and dust.
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HD 106906 is a binary star system in the southern constellation of Crux. It is too faint to be visible to the naked eye, having a combined apparent visual magnitude of 7.80. The distance to this system is approximately 337 light years based on parallax, and it is receding from the Sun with a radial velocity of +10 km/s. It is a member of the Lower Centaurus Crux group of the Scorpius–Centaurus OB association of co-moving stars.
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Iota Gruis, Latinized from ι Gruis, is a binary star system in the southern constellation of Grus. It has an apparent visual magnitude of 3.90, which is bright enough to be seen with the naked eye at night. The distance to this system, as determined using an annual parallax shift of 17.80 mas as seen from the Earth, is about 183 light years. This is a single-lined spectroscopic binary with an orbital period of and an eccentricity of 0.66.
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Psi3 Aquarii, Latinized from ψ3 Aquarii, is the Bayer designation for a visual binary star system in the constellation of Aquarius. It has an apparent visual magnitude of 4.98, which is bright enough to be seen with the naked eye. Parallax measurements give a distance estimate of roughly . The main component of this system is an A-type main sequence star with a stellar classification of A0 V. Its companion is an 11th magnitude star 1.5 arcseconds from the primary.
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Epsilon Cancri (ε Cancri, abbreviated Epsilon Cnc, ε Cnc) is a white-hued binary star system in the zodiac constellation of Cancer. It is the brightest member of the Beehive Cluster with an apparent visual magnitude of +6.29, which is near the lower limit of visibility with the naked eye. The annual parallax shift of as seen from Earth yields a distance estimate of approximately 616 light-years from the Sun. The binary pair has the designation WDS J08405+1933.
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HD 107148 is an 8th magnitude primary of the binary star system located approximately 161 light years away in the constellation of Virgo. It is a yellow dwarf with a luminosity 1.41 times the Sun. It is twice as enriched with heavy elements than the Sun. In 2012, a comoving white dwarf stellar companion HD 107148 B was detectedWide companions to Hipparcos stars within 67 pc of the Sun at projected separation of 1790 AU, and was confirmed in 2014.
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Kappa Leporis, Latinized from κ Leporis, is a binary star system in the southern constellation of Lepus. The pair have apparent visual magnitudes of 4.43 and 7.00, with the former being bright enough to be seen with the naked eye. As of 2000, they had an angular separation of 2.179 arc seconds along a position angle of 357.3°. Based upon an annual parallax shift of 4.48 mas as measured from Earth, the system is located roughly 730 light years from the Sun.
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Orbit of Procyon B seen from above its plane. Procyon is a binary star system with a bright primary component, Procyon A, having an apparent magnitude of 0.34, and a faint companion, Procyon B, at magnitude 10.7. The pair orbit each other with a period of 40.82 years along an elliptical orbit with an eccentricity of 0.407, more eccentric than Mercury's. The plane of their orbit is inclined at an angle of 31.1° to the line of sight with the Earth.
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The fainter star—Zeta2 Antliae—is 386 ± 5 light-years distant and of magnitude 5.9. Eta Antliae is another double composed of a yellow white star of spectral type F1V and magnitude 5.31, with a companion of magnitude 11.3. Theta Antliae is likewise double, most likely composed of an A-type main sequence star and a yellow giant. S Antliae is an eclipsing binary star system that varies in apparent magnitude from 6.27 to 6.83 over a period of 15.6 hours.
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SN 2004GT was a type Ic supernova that happened in the interacting galaxy NGC 4038 on December 12, 2004. The event occurred in a region of condensed matter in the western spiral arm. The progenitor was not identified from older images of the galaxy, and is either a type WC Wolf-Rayet star with a mass over 40 times that of the Sun, or a star 20 to 40 times as massive as the Sun in a binary star system.
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49 Cassiopeiae is a binary star system in the northern circumpolar constellation of Cassiopeia. It is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of 5.22. The system is located about 412 light years away from the Sun, based on parallax. The pair had an angular separation of along a position angle of 244°, as of 2008, with the brighter component being of magnitude 5.32 and its faint companion having magnitude 12.30.
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Thus it did not show a pre-eruption rise in brightness. This is an interacting binary star system consisting of a white dwarf primary star and a main sequence star with a stellar classification of G8V. The orbit has a period of 0.33381379 days and an inclination of 88.2° to the line of sight to the Earth, resulting in an eclipsing binary. The nova eruption is believed to have been driven by mass transferred from the secondary star to the white dwarf.
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NASA Exoplanet Exploration Program "travel poster" for Kepler-16b The planet orbits in a circumbinary orbit around a (K-type) and (M-type) binary star system. The stars orbit each other about every 41 days. The stars have masses of 0.68 and 0.20 and radii of 0.64 and 0.22 , respectively. They have surface temperatures of 4450 K and 3311 K. Based on the stellar characteristics and orbital dynamics, an estimated age of 2 billion years for the system is possible.
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31 Vulpeculae is a binary star system in the northern constellation of Vulpecula. It is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of 4.56. The system is located approximately 228 light years away from the Sun based on parallax, and it is drifting further away with a radial velocity of +2.25 km/s. The variable radial velocity of this system was first suspected by German Astronomer Friedrich Küstner in 1914.
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16 Serpentis is a binary star system in the Serpens Caput portion of the equatorial constellation of Serpens, located 228 light years from the Sun. It is visible to the naked eye as a fain, orange-hued star with an apparent visual magnitude of 5.261. The system is moving further from the Earth with a heliocentric radial velocity of +3 km/s. The variable radial velocity of this star was discovered at Lick Observatory and was announced by J. H. Moore in 1924.
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The presence of this gas creates an excess emission of infrared, along with emission lines in the star's spectrum. Most of it is concentrated around the equator, forming a disk. Some of the variation in this star may be explained by assuming it is a binary star system. This proposed secondary star would need to have about 4–7 times the Sun's mass and be orbiting with a period of at least 4.6 years at a minimum separation of 6.9 Astronomical Units.
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Eta Capricorni, Latinized from η Capricorni, is a binary star system in the southern constellation of Capricornus. It can be seen with the naked eye, having a combined apparent visual magnitude of +4.84. Based upon an annual parallax shift of 20.20 mas as seen from the Earth, the star is located about 161 light years from the Sun. The pair orbit each other with a period of 27.85 years, a semimajor axis of 0.265 arc seconds, an eccentricity of 0.410.
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This binary star system consists of two closely spaced low-mass red dwarfs. The secondary star is a dim magnitude 14 lost in the glare of the nearby primary star. The most recent determination of the system orbital elements comes from a study by George Gatewood using older sources along with data from the Hipparcos satellite. This study yielded an orbital period of about 16.6 years and a semi-major axis separation of about 1.1 arc seconds (2.4–5.3 AU).
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It is a slow irregular variable star of type Lb, undergoing changes in magnitude over the range 3.57−3.72 with a periodicity of 23.8 d. The measured angular diameter of Tau4 Eridani is . At its estimated distance, this yields a physical size of about 106 times the radius of the Sun. It shines with 1,537 times the luminosity of the Sun from an outer atmosphere at an effective temperature of 3,712 K. This is most likely a binary star system.
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The Hills mechanism is a phenomenon that occurs when a binary star system is disrupted by a supermassive black hole. Tidal forces from the black hole cause one of the stars to be captured by it, and fall into an orbit around it. The other star is jettisoned away from the black hole at very high speeds. The phenomenon was proposed by astronomer Jack Hills in 1988 and confirmed in 2019, when an example of such a jettisoned star was observed.
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Eta Canis Minoris (η CMi, η Canis Minoris) is a binary star system in the equatorial constellation of Canis Minor. It is approximately 318 light-years from Earth. The primary component, η Canis Minoris A, is a yellow-white F-type giant with an apparent magnitude of +5.24. Its companion, η Canis Minoris B, is an eleventh-magnitude star located 4 arcseconds from the primary, though is actually around 440 AU from the main star and takes around 5,000 years to orbit it.
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Tau Sculptoris (τ Scl, τ Sculptoris) is a binary star system in the southern constellation of Sculptor, about 8° to the east-southeast of Alpha Sculptoris. It is faintly visible to the naked eye with a combined apparent visual magnitude of +5.69. Based upon an annual parallax shift of 14.42 mas as seen from Earth, it is located around 230 light years from the Sun. The binary nature of this system was discovered by English astronomer John Herschel in 1835.
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Epsilon Trianguli, Latinized from ε Trianguli, is a binary star system in the northern constellation of Triangulum. Based upon measurement of its trigonometric parallax, it is approximately 390 light years from Earth. The primary component is an A-type main sequence star with a stellar classification of A2 V, an apparent magnitude of +5.50 and an estimated age of 600 million years. It has 2.75 times the mass of the Sun and is spinning with a projected rotational velocity of 107 km/s.
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HD 225218 is a quadruple star system in the northern constellation of Andromeda. The primary component, HD 225218 A, is a giant star with a stellar classification of B9III, an apparent magnitude of 6.16, and is a candidate Lambda Boötis star. It has a fainter, magnitude 9.65 companion, HD 225218 B, at an angular separation of 5.2″ along a position angle of 171°. The primary itself has been identified as a binary star system through interferometry, with the two components separated by 0.165″.
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Xi Ursae Majoris (ξ Ursae Majoris, abbreviated Xi UMa, ξ UMa), also named Alula Australis , is a star system in the constellation of Ursa Major. On May 2, 1780, Sir William Herschel discovered that this was a binary star system, making it the first such system ever discovered. It was the first visual double star for which an orbit was calculated, when it was computed by Félix Savary in 1828. It is also a variable star with a small amplitude.
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A colliding-wind binary is a binary star system in which the two members are massive stars that emit powerful, radiatively-driven stellar winds. The location where these two winds collide produces a strong shock front that can cause radio, X-ray and possibly synchrotron radiation emission. Wind compression in the bow shock region between the two stellar winds allows dust formation. When this dust streams away from the orbiting pair, it can form a pinwheel nebula of spiraling dust.
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An intermediate-mass X-ray binary (IMXB) is a binary star system where one of the components is a neutron star or a black hole. The other component is an intermediate mass star. Hercules X-1 is composed of a neutron star accreting matter from a normal star (HZ Her) probably due to Roche lobe overflow. X-1 is the prototype for the massive X-ray binaries although it falls on the borderline, , between high- and low-mass X-ray binaries.
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Omega Fornacis, which is Latinized from ω Fornacis, is a wide binary star system in the southern constellation of Fornax. It has a blue-white hue and is faintly visible to the naked eye as a fifth-magnitude star. The system lies at a distance of approximately 470 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +10 km/s. The dual nature of this system was discovered in 1836 by John Herschel.
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51 Eridani has a companion, known as GJ 3305. The system has a common proper motion with 51 Eridani, and hence it is gravitationally bound, although it is separated by 66″ corresponding to 2,000 AU. It is a binary star system with two M-type red dwarfs. The primary has a mass of while the secondary has a mass of . The two red dwarfs themselves are separated by a semimajor axis of 9.78 ± 0.14 AU and have an eccentricity of 0.19 ± 0.02.
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This is a probable single-lined spectroscopic binary star system. The visible component has a stellar classification of F3 V or F3 IV, indicating it is either an F-type main-sequence star or a somewhat more evolved subgiant star, respectively. It has an estimated 1.3 times the mass of the Sun and about 1.3 times the Sun's radius. The star is 1.75 billion years old and has a high rate of spin with a projected rotational velocity of around 97.5 km/s.
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A close binary star system occurs when two stars orbit each other with an average separation that is of the same order of magnitude as their diameters. At these distances, more complex interactions can occur, such as tidal effects, transfer of mass and even collisions. Tidal interactions in a close binary system can result in modification of the orbital and rotational parameters. The total angular momentum of the system is conserved, but the angular momentum can be transferred between the orbital periods and the rotation rates.
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59 Persei is a suspected astrometric binary star system in the northern constellation of Perseus. It is visible to the naked eye as a dim, white-hued star with an apparent magnitude of 5.30. The star is located around 256 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +13 km/s. This is an ordinary A-type main-sequence star with a stellar classification of A1Vn, a star that is fusing its core hydrogen.
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60 Sagittarii is a suspected binary star system in the southern constellation of Sagittarius. It has the Bayer designation A Sagittarii, while 60 Sagittarii is the Flamsteed designation. This naked eye object forms the northwest corner of the asterism called the Terebellum and, with an apparent magnitude of approximately 4.84, it is the dimmest of the four stars in the Terebellum. It is located 379 light years from the Sun, based on parallax, but is moving closer with a radial velocity of −51 km/s.
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HD 156846 is a binary star system in the equatorial constellation of Ophiuchus, positioned a degree SSE of Messier 9. It has a yellow hue and is just barely bright enough to be visible to the naked eye with an apparent visual magnitude of 6.5. The system is located at a distance of 156 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −68.5 km/s, and is predicted to come to within in about 476,000 years.
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88 Leonis is a wide binary star system in the equatorial constellation of Leo, the lion. The system is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.27. It is located at a distance of 77 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −4.8 km/s. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.379 arc seconds per annum.
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HD 12055 is a candidate astrometric binary star system in the southern constellation of Phoenix, near the eastern constellation border with Eridanus. It is yellow in hue and is visible to the naked eye with an apparent visual magnitude of 4.82. The system is located at a distance of approximately 249 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +13 km/s. The visible component is an aging giant star with a stellar classification of G6III-IIIb.
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Beta Delphini was found to be a binary star system in 1873 by the American astronomer S. W. Burnham. The system consists of a pair of F-type stars that orbit each other with a period of 26.66 years and an eccentricity of 0.36. The plane of the orbit is inclined by an angle of 61° to the line of sight from the Earth. The two stars have an angular separation of about 0.44 arcseconds, making them a challenge to resolve with a telescope.
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HD 21278 is a binary star system in the constellation Perseus, located within the million year old Alpha Persei Cluster. It has a blue-white hue and is visible to the naked eye with a combined apparent visual magnitude of 4.99. The system is located at a distance of approximately 580 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +1.20 km/s. The binary nature of this star was announced in 1925 by Otto Struve.
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One model for the formation of this category of supernova is a close binary star system. The progenitor binary system consists of main sequence stars, with the primary possessing more mass than the secondary. Being greater in mass, the primary is the first of the pair to evolve onto the asymptotic giant branch, where the star's envelope expands considerably. If the two stars share a common envelope then the system can lose significant amounts of mass, reducing the angular momentum, orbital radius and period.
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78 Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.93. Parallax estimates by Hipparcos put it at a distance of , but it is drifting closer with a radial velocity of −5 km/s. The system is a candidate member of the Ursa Major Moving Group. The binary nature of this system was announced by S. W. Burnham in 1894.
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75 Cygni is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a dim, reddish-hued point of light with an apparent visual magnitude of 5.09. The system is located at a distance of about 434 light years from the Sun, based on parallax, and is drifting closer with a radial velocity of −29 km/s. The pair had an angular separation of as of 2008, with the companion having a visual magnitude of 10.7.
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Gamma Columbae, Latinized from γ Columbae, is a possible wide binary star system in the southern constellation of Columba. It is visible to the naked eye with an apparent visual magnitude of 4.36. Based upon an annual parallax shift of 3.75 mas, it is located roughly 870 light years from the Sun. The primary component is an evolved B-type subgiant star with a stellar classification of B2.5 IV. It is a candidate slowly pulsating B-type star with a mean longitudinal magnetic field strength of .
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HD 5789 and HD 5788 is a pair of stars comprising a binary star system in the northern constellation of Andromeda. Located approximately away, the primary is a hot, massive blue star with an apparent magnitude of 6.06 while the secondary is slightly smaller and cooler, with an apparent magnitude of 6.76. Both stars are main-sequence stars, meaning that they are currently fusing hydrogen into helium in their cores. As of 2016, the pair had an angular separation of along a position angle of 195°.
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Cygnus contains the binary star system KIC 9832227. It is predicted that the two stars will coalesce in about 2022, briefly forming a new naked-eye object. Cygnus is one of the constellations that the Kepler satellite surveyed in its search for extrasolar planets, and as a result, there are about a hundred stars in Cygnus with known planets, the most of any constellation. One of the most notable systems is the Kepler-11 system, containing six transiting planets, all within a plane of approximately one degree.
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Iota Crateris (ι Crateris) is the Bayer designation for a binary star system in the southern constellation of Crater. It is faintly visible to the naked eye with an apparent visual magnitude of 5.48. According to the Bortle scale, this means it can be viewed from suburban skies at night. Based upon an annual parallax shift of 37.41 mas, Iota Crateris is located 87 light years from the Sun. This is an astrometric binary system with an estimated orbital period of roughly 79,000 years.
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Theta Circini (θ Cir), is a binary star located in the southern constellation of Circinus, to the northwest of Alpha Circini. It is faintly visible to the naked eye with an apparent visual magnitude of 5.110. Based upon an annual parallax shift of 11.82 mas, it is located at a distance of about 276 light years from the Sun. This is an astrometric binary star system with an orbital period of about 39.6 years, an eccentricity of 0.3, and a semimajor axis of 85.64 mas.
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HD 44780 is a binary star system in the northern constellation of Gemini, located about 3° north of Mu Geminorum. The pair have a combined apparent visual magnitude of 6.35, which is near the lower limit of visibility to the naked eye. Although it is above magnitude 6.5, it was not included in the Bright Star Catalogue; the designation HD 44780 comes from the Henry Draper catalogue. Based upon parallax measurements, the system is located at a distance of approximately 960 light years from the Sun.
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BU Canis Minoris is a binary star system in the equatorial constellation of Canis Minor. It has the Henry Draper Catalogue designation of HD 65241, while BU Canis Minoris is its variable star designation. The system is a challenge to view with the naked eye, having a peak apparent visual magnitude of 6.42. It is located at a distance of approximately 700 light years from the Sun based on parallax, and is drifting further away with a radial velocity of about +34 km/s.
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16 Puppis is a suspected astrometric binary star system in the southern constellation of Puppis, and is located in the northernmost part of its constellation, almost due north of the bright star Rho Puppis, and east of Canis Major. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.40. The star is located is approximately 465 light years away from the Sun based on parallax. It was the brightest star in Officina Typographica, an obsolete constellation.
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Xi Columbae is a binary star system in the southern constellation of Columba. With an apparent visual magnitude of 4.97, it is faintly visible to the naked eye. Based upon an annual parallax shift of , it is located around 323 light years from the Sun. The system is a member of the HR 1614 supergroup, and is drifting further away with a radial velocity of +59.5 km/s, This is an astrometric binary with an orbital period of 1,420.6 days and an eccentricity of 0.39.
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Iota1 Cygni, Latinized from ι1 Cygni, is a probable binary star system in the northern constellation Cygnus, and is separated by less than a degree from its brighter visual neighbor, Iota2 Cygni. It is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 5.75. The system is located approximately 387 light years away based on parallax, and it is drifting further away with a radial velocity of +2 km/s. This is a candidate double-lined spectroscopic binary system.
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Delta Piscis Austrini (δ Piscis Austrini) is a yellow-hued star in the southern constellation of Piscis Austrinus. It is visible to the naked eye with an apparent visual magnitude of +4.175. There is a magnitude 9.86 common proper motion companion located at an angular separation of 5.2 arc seconds – the pair most likely form a binary star system. Based upon an annual parallax shift of 18.9796 mas as seen from the Gaia satellite, Delta Piscis Austrini is located 172 ± 2 light-years from the Sun.
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Zeta Pyxidis (ζ Pyxidis) is a wide binary star system in the southern constellation of Pyxis. It is visible to the naked eye with a combined apparent visual magnitude of +4.88. Based upon an annual parallax shift of 13.35 mas as seen from Earth, it is located around 244 light years from the Sun. The yellow-hued primary, component A, is an evolved G-type giant star with a stellar classification of , where the suffix notation indicating it has anomalously weak lines of cyanogen.
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Iota Apodis (ι Aps, ι Apodis) is the Bayer designation for a binary star system in the southern circumpolar constellation of Apus. It is a faint target at an apparent visual magnitude of 5.41, but still visible to the naked eye from suitably dark skies. The distance to this star can be roughly gauged from parallax measurements, yielding an estimate of with a 20% margin of error. Both stars are B-type main sequence stars, which indicates they shine with a blue-white hue.
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5 Aurigae is a triple star system in the northern constellation of Auriga, located about 195 light years away from the Sun based on parallax. It is just visible to the naked eye as a dim, yellow-white hued star with an apparent visual magnitude of 5.95. The system is moving away from the Earth with a heliocentric radial velocity of +6 km/s, having come within some 8.7 million years ago. This was initially discovered to be a binary star system by Otto Struve.
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14 Aquilae is a probable spectroscopic binary star system in the equatorial constellation of Aquila. 14 Aquilae is the Flamsteed designation though it also bears the Bayer designation g Aquilae. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.42, and it is located at a distance of approximately from Sun. The star is moving closer to the Earth with a heliocentric radial velocity of , and may come as close as in around 3.5 million years.
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6 Andromedae is an astrometric binary star system in the northern constellation of Andromeda. The designation comes from the star catalogue of John Flamsteed, first published in 1712. Its apparent visual magnitude is 5.91, which is just bright enough to be visible to the naked eye under good seeing conditions. Based upon an annual parallax shift of 34.1 mas as seen from Earth, it is around 96 light years from the Sun. It is moving closer to the Sun with a radial velocity of −32.4 km/s.
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46 Boötis is a binary star system in the northern constellation of Boötes, located mid-way between α Coronae Borealis and ε Boötis. It has the Bayer designation b Boötis; 46 Boötis is the Flamsteed designation. The system lies 478 light years away from the Sun based on parallax, and is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 5.67. It is moving away from the Earth with a heliocentric radial velocity of +19 km/s.
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3 Boötis is a close binary star system in the northern constellation of Boötes, located 310 light years away from the Sun based upon parallax. It can be viewed with the naked eye in excellent seeing conditions as a dim star with an apparent visual magnitude of 5.97. The system is moving further from the Earth with a heliocentric radial velocity of 12 km/s. This is a double-lined spectroscopic binary system with an orbital period of 36 days and an eccentricity of 0.543.
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Tau Librae, Latinized from τ Librae, is the Bayer designation for a binary star system at the southern edge of the zodiac constellation of Libra. It can be seen with the naked eye, having an apparent visual magnitude of 3.68. The distance to this system is around 367 light years, as determined from an annual parallax shift of 8.89 mas. Judging by its motion through space and physical properties, this system is a member of the Upper Centaurus Lupus group of the Scorpius-Centaurus Association.
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39 Eridani is a wide binary star system in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 4.87. As of 2015, the components had an angular separation of along a position angle of 143°. The system is moving further from the Sun with a heliocentric radial velocity of +7 km/s. The magnitude 5.07 primary, designated component A, is an aging giant star with a stellar classification of K3 III.
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Kepler-47 is a binary star system located about away from Earth. The binary system is composed of a G-type main sequence star (Kepler-47A) and a red dwarf star (Kepler-47B). The stars orbit each other around their barycenter, or center of mass between them, completing one full orbit every 7.45 days. The stars orbit their barycenter from a distance of about 0.084 AU. The stars have 104% and 35% of the Sun's mass, and 96% and 35% of the Sun's radius, respectively.
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HD 20644 is a suspected binary star system in the constellation Aries. It has an orange hue and is visible to the naked eye with an apparent visual magnitude of 4.47. The system is located at a distance of approximately 540 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −3 km/s. The visible component is an aging giant star with a stellar classification of K3IIIa Ba0.5, where the suffix notation indicates this is a mild barium star.
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3 Monocerotis is a binary star system in the equatorial constellation of Monoceros, located approximately 780 light years away from the Sun based on parallax. It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.92. The system is moving further from the Earth with a heliocentric radial velocity of +39 km/s. The magnitude 4.98 primary, designated component A, has a stellar classification of B5 III, matching an evolved blue giant star.
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HD 90264 is a binary star system in the southern constellation of Carina. It has the Bayer designation of L Carinae, while HD 90264 is the star's identifier in the Henry Draper catalogue. This system has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.97. It is located at a distance of approximately 402 light years from the Sun based on parallax, and is drifting further away with a radial velocity of around +12 km/s.
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HD 76728 is a suspected astrometric binary star system in the constellation Carina. It has the Bayer designation c Carinae; HD 76728 is the identifier from the Henry Draper catalogue. The visible component has a blue-white hue and is visible to the naked eye with an apparent visual magnitude of +3.84. The system is located at a distance of approximately 320 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of around +25 km/s.
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Tau Puppis (Tau Pup, τ Puppis, τ Pup) is a star in the southern constellation of Puppis. It has an apparent visual magnitude of +2.95 and is located at a distance of about from Earth. This is a spectroscopic binary star system, with the presence of the secondary component being revealed by the shifts of absorption lines in the spectrum resulting from the Doppler effect. The two components orbit each other with a period of 1,066.0 days (2.9 years) and a low eccentricity of 0.090.
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26 Hydrae is a binary star system located 334 light years away from the Sun in the equatorial constellation of Hydra. It is visible to the naked eye as a faint, yellow-hued point of light with a combined apparent visual magnitude of 4.77, just a few degrees away from Alphard. The system is moving closer to the Earth with a leisurely radial velocity of -1 km/s. Keenan and McNeil (1989) gave the brighter component a stellar classification of G7 III, matching an aging giant star.
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26 Vulpeculae is a close binary star system in the northern constellation of Vulpecula, around 644 light years away from the Sun. It is a challenge to view with the naked eye, having an apparent visual magnitude of 6.40. The star is moving closer to the Earth with a heliocentric radial velocity of −63 km/s, and is expected to come within in around 2.6 million years. This is a single- lined spectroscopic binary with an orbital period of 11 days and an eccentricity of 0.28.
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This is a suspected binary star system, with a companion star at an angular separation of along a position angle of from the primary, as of 2008. This corresponds to a projected separation of . The brighter component is an A-type main sequence star with a stellar classification of A3 V. The system is a source of X-ray emission with a luminosity of , which is most likely originating from the cooler companion since A-type main sequence stars are not expected to be magnetically active.
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HD 34968 is a binary star system in the southern constellation Lepus. The combined apparent visual magnitude of 4.69 is bright enough to be visible to the naked eye. The distance to HD 34968 can be estimated from its annual parallax shift of , yielding a range of 374 light years. It is moving further away from the Earth with a heliocentric radial velocity of 31 km/s, having come within some 3,686,000 years ago. The primary member, component A, is a magnitude 4.73 star.
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Astronomers made more sense of its pulsations when it became clear that it is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85 ± 0.05 times as massive as the Sun. Its companion is most likely a red dwarf of spectral type M3V, around 0.3 times as massive as the Sun. The two are very close—possibly only 3 times the diameter of the Sun between them—and orbit each other every 1.15 days.
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Her 1951 calculations of the orbit of the difficult astronomical binary star system Ross 614 were used to successfully find and image the system's secondary star. These calculations were used by Walter Baade to find and optically resolve this binary system for the first time using the then new Hale Telescope at the Palomar Observatory in California. She is listed as professor emerita of astronomy and director emerita of the Sproul Observatory in the 2010 Swarthmore college catalog. She last published astronomy research papers in 1983.
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HD 202206 is a binary star system in the southern constellation of Capricornus. With an apparent visual magnitude of +8.1, it is too faint to be visible to the naked eye. It is located at a distance of 150 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +14.7 km/s. The primary component is a G-type main-sequence star with a stellar classification of G6V, indicating it is generating energy through core hydrogen fusion.
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They are all considered to be cataclysmic variable stars. Classical nova eruptions are the most common type. They are likely created in a close binary star system consisting of a white dwarf and either a main sequence, subgiant, or red giant star. When the orbital period falls in the range of several days to one day, the white dwarf is close enough to its companion star to start drawing accreted matter onto the surface of the white dwarf, which creates a dense but shallow atmosphere.
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PSR B1259−63 is a pulsar and member of an eclipsing binary star system with the blue O9.5Ve-class star LS 2883. The pair has an eccentric orbit that is inclined to the line of sight from Earth by about 36°, leading to a 40-day- long eclipse each time the pulsar passes behind the star. The pulsar has a period of about 48 ms and a luminosity of . It emits very high energy gamma rays that vary on a time scale of several days.
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This is an astrometric binary star system. The best fit to the radial velocity data yields an orbital period of roughly 13,770 days (37.7 years) with an eccentricity of around 0.28. The semimajor axis of their computed orbit is about 13 au, or 13 times the distance of the Earth from the Sun. The primary, component A, is an evolved K-type subgiant star with a stellar classification of , where the suffix notation indicates the absorption lines of iron and the carbon-hydrogen bond are abnormally weak.
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The Antennae Galaxies appear in a telescope at the 10th magnitude. SN 2004gt was a type Ic supernova that erupted on December 12, 2004. The progenitor was not identified from older images of the galaxy, and is either a type WC Wolf–Rayet star with a mass over 40 times that of the Sun, or a star 20 to 40 times as massive as the Sun in a binary star system. SN 2007sr was a Type Ia supernova event that peaked in brightness on December 14, 2007.
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HD 163840 is a binary star system in the northern constellation of Hercules. It has a combined apparent visual magnitude of 6.45, which falls just below the brightness level that is visible to the naked eye for people with normal eyesight. An annual parallax shift of 35.40 mas provides a distance estimate of about 92 light years. The system is moving closer to the Sun with a radial velocity of −33 km/s. In about 769,000 years, it will make perihelion at a separation of around .
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Artist's impression of R Aquarii, a symbiotic binary, during an active phase A symbiotic binary is a type of binary star system, often simply called a symbiotic star. They usually contain a white dwarf with a companion red giant. The cool giant star loses material via Roche lobe overflow or through its stellar wind, which flows onto the hot compact star, usually via an accretion disk. Symbiotic binaries are of particular interest to astronomers as they can be used to learn about stellar evolution.
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Kepler-16 is an eclipsing binary star system in the constellation of Cygnus that was targeted by the Kepler spacecraft. Both stars are smaller than the Sun; the primary, Kepler-16A, is a K-type main-sequence star and the secondary, Kepler-16B, is an M-type red dwarf. They are separated by 0.22 AU, and complete an orbit around a common center of mass every 41 days. The system is host to one known extrasolar planet in circumbinary orbit: the Saturn-sized Kepler-16b.
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66 Cancri is a binary star system near the northern border of the zodiac constellation of Cancer, located 474 light years away from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.87. The pair are moving closer to the Earth with a heliocentric radial velocity of −13 light years. As of 2003, the magnitude 8.56 companion was located at an angular separation of along a position angle of 134° from the primary.
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20 Cancri is an astrometric binary star system in the constellation Cancer, located about 348 light years away from the Sun. This system has the Bayer designation d1 Cancri; 20 Cancri is the Flamsteed designation. It is just visible to the naked eye under good viewing conditions, appearing as a dim, white-hued star with an apparent visual magnitude of 5.94. The pair are moving further from the Earth with a heliocentric radial velocity of +36 km/s, and are members of the Hyades Supercluster.
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83 Cancri is an astrometric binary star system in the northern constellation of Cancer, positioned near the constellation border with Leo. It is a challenge to view with the naked eye, having an apparent visual magnitude of 6.61. Despite having a Flamsteed designation, the system was too faint to be included in the Bright Star Catalogue. It is located at a distance of 133 light years from the Sun, based on parallax, but is drifting closer with a radial velocity of −15 km/s.
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FL Lyrae is the variable star designation for an eclipsing binary star system in the northern constellation of Lyra. The combined apparent magnitude of the pair is 9.36, which means they are too faint to be seen with the naked eye. Parallax measurements from the Hipparcos spacecraft put the system at a distance of around 420 light years from the Sun. This star system was in the view field of the Kepler space telescope during 2009−2014, which allowed monitoring during that spacecraft's mission.
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54 Eridani is a suspected astrometric binary star system located around 400 light years from the Sun in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, reddish hued star with a baseline apparent visual magnitude of 4.32. The object is moving closer to the Earth with a heliocentric radial velocity of −33 km/s. The visible component is an aging red giant star, currently on the asymptotic giant branch, with a stellar classification of M3/4 III.
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HD 37017 is a binary star system in the equatorial constellation of Orion. It has the variable star designation V1046 Orionis; HD 37017 is the identifier from the Henry Draper Catalogue. The system is a challenge to view with the naked eye, being close to the lower limit of visibility with a combined apparent visual magnitude of 6.55. It is located at a distance of approximately 1,230 light years based on parallax, and is drifting further away with a radial velocity of +32 km/s.
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UW Coronae Borealis, also known as MS 1603.6+2600, is a low-mass X-ray binary star system in the constellation Corona Borealis. Astronomer Simon Morris and colleagues discovered the X-ray source in 1990 and were able to match it up with a faint star with an average visual magnitude of 19.4. The system is thought to be made up of a neutron star that has an accretion disk that draws material from its companion, a star less massive than the Sun. The disk is asymmetrical.
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Theta Ursae Majoris (Theta UMa, θ Ursae Majoris, θ UMa) is a suspected spectroscopic binary star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of 3.17, placing it among the brighter members of this constellation. The distance to this star has been measured directly using the parallax method, yielding an estimated value of . In 1976, this was reported as a spectroscopic binary system by Helmut A. Abt and Saul G. Levy, giving it an orbital period of 371 days.
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31 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis. It is visible to the naked eye as a dim point of light with a peak apparent visual magnitude of +5.12. Parallax measurements provide a distance estimate of approximately 460 light years away from the Sun, and the system is drifting closer to the Earth with a radial velocity of −3 km/s. This is a single-lined spectroscopic binary in a circular orbit with an orbital period of 2.93 days.
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53 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis, located 290 light years away from the Sun as determined by parallax measurements. It has the variable star designation AX Camelopardalis; 53 Camelopardalis is the Flamsteed designation. This object is dimly visible to the naked eye as a white hued star with a baseline apparent visual magnitude of +6.02. It is a single-lined spectroscopic binary system with an orbital period of 6.63 years and a high eccentricity of 0.718.
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55 Cancri is a binary star system located 41 light-years away from the Sun in the zodiac constellation of Cancer. It has the Bayer designation Rho1 Cancri (ρ1 Cancri); 55 Cancri is the Flamsteed designation (abbreviated 55 Cnc). The system consists of a K-type star (designated 55 Cancri A, also named Copernicus ) and a smaller red dwarf (55 Cancri B). , five extrasolar planets (designated 55 Cancri b, c, d, e and f; named Galileo, Brahe, Lipperhey, Janssen and Harriot, respectively) are believed to orbit 55 Cancri A.
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49 Librae is the Flamsteed designation for a binary star system in the Zodiac constellation of Libra. It has an apparent visual magnitude of 5.47, making it faintly visible to the naked eye from dark suburban skies as a dim, yellow- white hued star. The system is located 95 light years away from the Sun, based on parallax, but is drifting closer with a radial velocity of −20 km/s. The variable nature of the velocity for 49 Librae was first noted by W. S. Adams in 1924.
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38 Leonis Minoris is a binary star system in the northern constellation of Leo Minor. It shines with a combined light of apparent magnitude 5.84, which indicates it a dimly visible to the naked eye under good viewing conditions. An annual parallax shift of 19.11 mas provides a distance estimate of around 171 light years. It has a relatively high proper motion, traversing the celestial sphere at a rate of 0.226 arcseconds per year, and is moving away from the Sun with a radial velocity of +31 km/s.
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HD 41004 is a visual binary star system in the southern constellation of Pictor. It is too faint to be visible to the naked eye, having a combined apparent visual magnitude of 8.65. The two components have a magnitude difference of 3.7, and share a common proper motion with an angular separation of , as of 2018. The distance to this system is approximately 136 light years based on parallax. It is drifting further away from the Sun with a radial velocity of +42.5 km/s, having come to within some 831,000 years ago.
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This is a spectroscopic binary star system with an orbital period of 45.1 days and an eccentricity of 0.26. The primary component is a B-type subgiant star with a stellar classification of B3 IV. With an estimated age of just 32 million years, it has a relatively high rate of spin, showing a projected rotational velocity of 160 km/s. Xi Orionis has about 6.7 times the mass of the Sun, and shines with 1,390 times the solar luminosity from its outer atmosphere at an effective temperature of 15,476 K.
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Mu Canis Majoris (μ Canis Majoris) is a binary star system in the southern constellation of Canis Major. The pair can be located a little to the southwest of the point midway between Gamma and Theta Canis Majoris, and the components can be split with a small telescope. The system is faintly visible to the naked eye with an apparent visual magnitude of 5.12. Based upon an annual parallax shift of just 2.62 mas as seen from Earth, this system is located roughly 1,200 light years from the Sun.
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This is a single-lined spectroscopic binary star system with an orbital period of 1.66 years and an eccentricity of 0.14. The primary is a red giant of spectral type K3-IIIb Fe-0.5, a star that has used up its core hydrogen and is expanding. The suffix notation indicates the spectrum displays a mild underabundance of iron for a star of its type. It has expanded to around 28 times the Sun's radius and is radiating 437 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,165 K.
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The radial velocity measurement is poorly constrained, but it appears to be drifting closer to the Sun at the rate of around −3 km/s. This is a double-lined spectroscopic binary star system with an orbital period of 11.6 days and an eccentricity of 0.26. The orbit for this star was first determined by R. H. Baker in 1912, then later revised. The primary, designated component A, is an Ap type chemically-peculiar star with a stellar classification of A1:VpSiSrHg, although it has also been considered to be a mercury-manganese star.
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Stars of this type have oddly localised magnetic fields and are slightly variable. Alpha Circini forms a binary star system with an orange dwarf companion of spectral type K5 and magnitude 8.5, which with a separation of 5.7 arcseconds is only discernible with a telescope. The distance between the two stars is 260 AU and they take 2600 years to rotate around a common centre of gravity. The second brightest star is Beta Circini, a white main sequence star of spectral type A3Va and a magnitude of 4.07, about 100 light- years away.
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Educated at the University of South Florida and the University of California, Santa Barbara, Boss is a prominent scientist in stellar and planetary system formation and the study of extrasolar planets who has made highly cited contributions to the study of gas giant planet and binary star system formation. He has published hundreds of articles in these areas and related fields. He is currently a Staff Member at the Carnegie Institution for Science in the Department of Terrestrial Magnetism. He is married to Catherine Ann Starkie and has two children.
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The very low abundance of these elements in globular clusters means that the member stars have a far lower likelihood of hosting Earth-mass planets, when compared with stars in the neighborhood of the Sun. Hence the halo region of the Milky Way galaxy, including globular cluster members, are unlikely to host habitable terrestrial planets. In spite of the lower likelihood of giant planet formation, just such an object has been found in the globular cluster Messier 4. This planet was detected orbiting a pulsar in the binary star system PSR B1620-26.
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Flanking Alpha to the east is Gamma Coronae Borealis, yet another binary star system, whose components orbit each other every 92.94 years and are roughly as far apart from each other as the Sun and Neptune. The brighter component has been classed as a Delta Scuti variable star, though this view is not universal. The components are main sequence stars of spectral types B9V and A3V. Located 170±2 light-years away, 4.06-magnitude Delta Coronae Borealis is a yellow giant star of spectral type G3.5III that is around and has swollen to .
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RS Coronae Borealis is yet another semiregular variable red giant, which ranges between magnitudes 8.7 to 11.6 over 332 days. It is unusual in that it is a red star with a high proper motion (greater than 50 milliarcseconds a year). Meanwhile, U Coronae Borealis is an Algol-type eclipsing binary star system whose magnitude varies between 7.66 and 8.79 over a period of 3.45 days TY Coronae Borealis is a pulsating white dwarf (of ZZ Ceti) type, which is around 70% as massive as the Sun, yet has only 1.1% of its diameter.
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These stars represent a late stage in the evolution of some stars, caused when a red giant star loses its outer hydrogen layers before the core begins to fuse helium. The reasons why this premature mass loss occurs are unclear, but the interaction of stars in a binary star system is thought to be one of the main mechanisms. Single subdwarfs may be the result of a merger of two white dwarfs. The sdB stars are expected to become white dwarfs without going through any more giant stages.
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Orbital plot of Proxima Centauri as presently seen from Earth Ever since the discovery of Proxima, it has been suspected to be a true companion of the Alpha Centauri binary star system. Data from the Hipparcos satellite, combined with ground-based observations, were consistent with the hypothesis that the three stars are a bound system. For this reason, Proxima is sometimes referred to as Alpha Centauri C. Kervella et al. (2017) used high-precision radial velocity measurements to determine with a high degree of confidence that Proxima and Alpha Centauri are gravitationally bound.
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3 Piscis Austrini, also known as HD 201901, is a suspected astrometric binary star system that, despite its Flamsteed designation, is actually located in the constellation Microscopium. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.41. The system is moving closer to the Earth with a heliocentric radial velocity of −46 km/s. It is following a highly elliptical orbit around the Galactic Center, moving between a pericenter of out to an apocenter of , with an orbital eccentricity of 0.49.
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Double Star is a two-player game about space warfare, and operates on the belief that warfare between two star systems is possible but expensive and difficult. This game is based in a binary star system, where the two stars orbit each other, and each star has a different colony orbiting it. Each colony has both antipathy for the other colony and something the other colony needs, and so war begins. The board features both worlds as they orbit their respective stars, and both stars orbiting each other.
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AZ Canis Minoris is a variable star in the equatorial constellation of Canis Minor. It is just visible to the naked eye in good viewing conditions as a dim, white-hued star with an apparent visual magnitude of around 6.46. The star is located around 500 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +15 km/s. No evidence has been found for a companion to this star, although in the past it has been reported as a binary star system.
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HR 7135 is a binary star system. Despite its Flamsteed designation of 62 Serpentis, the star can be found in the equatorial constellation of Aquila, in front of a dark rift in the Milky Way near the constellation border. It is visible to the naked eye as a dim, yellow-hued point of light with an apparent visual magnitude of 5.57. The system is located 283 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of 23 km/s.
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79 Ceti, also known as HD 16141, is a binary star system located 123 light- years from the Sun in the southern constellation of Cetus. It has an apparent visual magnitude of +6.83, which puts it below the normal limit for visibility with the average naked eye. The star is drifting closer to the Earth with a heliocentric radial velocity of −51 km/s. Harlan (1974) assigned this star a stellar classification of G2V, matching an ordinary G-type main-sequence star that is undergoing core hydrogen fusion.
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In 2008 a study was undertaken of 14 stars with exoplanets that were originally discovered using the transit method through relatively small telescopes. These systems were re-examined with the 2.2M reflector telescope at the Calar Alto Observatory in Spain. This star system, along with two others, was determined to be a previously unknown binary star system. The previously unknown secondary star is a dim magnitude 14 K or M-type star separated by about 755 AU from the primary, appearing offset from the primary by about one arc second in the images.
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Pi Piscis Austrini, Latinized from π Piscis Austrini, is binary star system in the southern constellation of Piscis Austrinus, near the eastern constellation border with Sculptor. It has a yellow-white hue and is visible to the naked eye as a dim point of light with an apparent visual magnitude of 5.12. The system is located at a distance of 92 light-years from the Sun based on parallax. Its radial velocity is poorly constrained, but it appears to be drifting closer at a rate of around −6 km/s.
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At the center of the nebula is a close binary star system with an orbital period of just 3.68 hours, one of the shortest known among the binary central stars that form a planetary nebulae. Their proximity to each other provides strong evidence that they have passed through a common-envelope (CE) phase earlier in their evolution. The pair may now consist of a primary star with , a red dwarf secondary companion having , and a semimajor axis of only . The surrounding nebula is inclined about 85° to the line of sight from the Earth.
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In 2008 a study was undertaken of fourteen stars with exoplanets that were originally discovered using the transit method through relatively small telescopes. These systems were re-examined with the 2.2M reflector telescope at the Calar Alto Observatory in Spain. This star system, along with two others, was determined to be a previously unknown binary star system. The previously unknown secondary star is a dim magnitude 15 K-type star separated by about 232 AU from the primary, appearing offset from the primary by about one arc second in the images.
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HD 142 is a wide binary star system in the southern constellation of Phoenix. The main component has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.7. The system is located at a distance of 85.5 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +6 km/s. The primary component is an F-type main-sequence star with a stellar classification of F7V, which indicates it is undergoing core hydrogen fusion.
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42 Cassiopeiae is a possible binary star system in the northern circumpolar constellation of Cassiopeia. It is visible to the naked eye as a dim, blue- white hued star with a baseline apparent visual magnitude of +5.18. The system is located approximately 291 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +7 km/s. This is classified as a suspected eclipsing binary of the Algol type, with a period of 16.77 days and a magnitude decrease of 0.3.
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60 Aurigae is a binary star system in the northern constellation of Auriga. The pair have a combined apparent visual magnitude of 6.319 and, based upon parallax measurements, they are approximately distant from the Earth. The combined spectrum of the pair match a stellar classification of F5 V. The primary component may be an A-type star with an apparent magnitude of 6.47, while the fainter, 8.96 magnitude secondary is possibly a G-type star. The pair orbit each other with a period of 271.1 years at an angular separation of 0.793 arcseconds.
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2 Aurigae in optical light 2 Aurigae is a possible binary star system in the northern constellation of Auriga. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of +4.79. It forms an attractive four-star asterism when viewed in a low power eyepiece, together with the nearby HIP 22647 and another very loose visual pair, HIP 22776 and HIP 22744, all above magnitude 8. 2 Aurigae is moving closer to the Earth with a heliocentric radial velocity of −17 km/s.
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Gamma Lupi (γ Lupi, γ Lup) is a 3rd-magnitude, B-type blue giant star in the constellation of Lupus. It is also known in ancient Chinese astronomy as 騎官一 or "the 1st (star) of the Cavalry Officer". With a telescope, Gamma Lupi can be resolved into a binary star system in close orbit. This is known as the Gamma Lupi AB system, often abbreviated as γ Lupi AB or γ Lup AB. Gamma Lupi A is itself a spectroscopic binary with a period of 2.8081 days.
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23 Orionis is a double star located around 1,200 light years away from the Sun in the equatorial constellation of Orion. It is visible to the naked eye as a dim, blue-white hued point of light with a combined apparent visual magnitude of 4.99. The pair are moving away from the Earth with a heliocentric radial velocity of +18 km/s, and they are members of the Orion OB1 Association, subgroup 1a. Howe and Clarke (2009) catalog this as a double-lined spectroscopic binary star system with a wide projected separation of .
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RU Ursae Minoris is a binary star system in the constellation Ursa Minor. Its apparent magnitude ranges from 10 to 10.66 over 0.52 days as one star passes in front of the other relative to observers on Earth. Its component stars were calculated to be a primary star of spectral type F0IV/V and a secondary of spectral type K5V, both slightly more luminous than their spectral types indicate. The system is semidetached, as the secondary star is filling its Roche lobe and transferring matter to the primary.
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81 Geminorum is a binary star system in the northern constellation of Gemini. It has the Bayer designation g Geminorum, while 81 Geminorum is its Flamsteed designation. This system is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.89. The pair are located approximately 360 light years away from the Sun, based on parallax, and are moving further away with a radial velocity of +83 km/s, having come to within an estimated of the Earth nearly a million years ago.
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In the year 2600 much of the Earth's population have left their home world and formed colonies on the worlds of the Besalius binary star system. All seemed peaceful in these fledgling colonies but as the last shuttle arrived in 2602 they were attacked by a terrifying alien race that would be nicknamed "The Breed". These attacks seemed to be random with little or no thought or logic, but they were devastating nevertheless. Under such an assault the colonies had no choice but to send out a distress call to Earth.
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18 Monocerotis is a binary star system located about half way from Orion's Belt to Procyon, in the equatorial constellation of Monoceros. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.47, and is positioned around 370 light years away from the Sun based on parallax. The system is receding from the Earth with a heliocentric radial velocity of +11 km/s. It is reported as a single-lined spectroscopic binary with an orbital period of and an eccentricity of 0.4.
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Epsilon Arietis (ε Ari, ε Arietis) is the Bayer designation for a visual binary star system in the northern constellation of Aries. It has a combined apparent visual magnitude of 4.63 and can be seen with the naked eye, although the two components are too close together to be resolved without a telescope. With an annual parallax shift of 9.81 mas, the distance to this system can be estimated as , give or take a 30 light-year margin of error. The brighter member of this pair has an apparent magnitude of 5.2.
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Omicron Capricorni (ο Capricorni) is a wide binary star system in the constellation Capricornus. The brighter component has an apparent visual magnitude of +5.94, which is near the lower limit on stellar brightness that still can be seen with the naked eye. Based upon an annual parallax shift of 15.07 mas as seen from Earth, this system is located roughly 220 light years from the Sun. Large but uncertain discrepancies in the parallax measurements from Hipparcos may indicate, weakly, that there is a third, unseen companion in the system.
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Wolf 424 is a binary star system comprising two red dwarf stars at a distance of approximately 14.2 light years from the Sun. It is located in the constellation Virgo, between the stars ε Virginis and ο Virginis. The close binary nature of this star was discovered by Dutch American astronomer Dirk Reuyl in 1941, based upon an elongation of the star found in photographs. The two stars in the Wolf 424 system orbit about each other with a semi-major axis of 4.1 AU and an eccentricity of 0.3.
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136 Tauri is a white-hued binary star system in the zodiac constellation of Taurus. It has a combined apparent visual magnitude of 4.56, which is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of as seen from Earth's orbit, it is located approximately 420 light years from the Sun. The system is moving nearer with a heliocentric radial velocity of −17.2 km/s, and is expected to make its closest approach in 6.5 million years at a distance of .
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Sigma Herculis, Latinized from σ Her, is a binary star system in the northern constellation of Hercules. It has a combined apparent visual magnitude of 4.18, making it bright enough to be visible to the naked eye. Based upon an annual parallax shift of 10.36 mas as seen from Earth, Sigma Herculis is located about 310 light years away from the Sun. The components of this binary system have a separation of 7 AU, and are orbiting their common barycenter with a period of 7.4 years and an eccentricity of 0.5.
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Alpha Doradus (Alpha Dor, α Doradus, α Dor) is the brightest star in the southern constellation of Dorado. The distance to this system, as measured using the parallax method, is about . This is a binary star system with an overall apparent visual magnitude that varies between 3.26 and 3.30, making this one of the brightest binary stars. The system consists of a subgiant star of spectral type B revolving around a giant star with spectral type A in an eccentric orbit with a period of about 12 years.
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This is a suspected binary star system for which orbital elements have been published, listing a circular orbit with period of 51.3 days. However, sources do not confirm this and so the binarity remains in doubt. The observable component is a G-type main sequence star with a stellar classification of , indicating abnormal deficiencies in iron and the CH molecule. The surface magnetic activity for this star is distinctly lower than the typical level for regular stars, and hence it is considered a good candidate for being in a Maunder minimum phase.
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The star is radiating 29.5 times the Sun's luminosity from its photosphere at an effective temperature of 8,840 K. The remaining components form a binary star system with an orbital period of 56 years, an angular semimajor axis of , and an eccentricity of 0.13. They have an angular separation of from the primary. The total mass of the pair is and they have a combined visual magnitude of 8.85. The brighter member of this pair is a suspected K-type main-sequence star with a class of K0V.
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KELT-2A (also called KELT-2, HD 42176, or HD 42176A) is a yellow white dwarf star located about 440 light-years away in the constellation Auriga. The apparent magnitude of this star is 8.77, which means it is not visible to the naked eye but can be seen with a binoculars. KELT-2A is the brightest star in the common-proper-motion binary star system KELT-2 (HD 42176). KELT-2B is an early K dwarf approximately 295 AU away, which was discovered simultaneously with the planet KELT-2Ab.
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HD 2454 is a probable binary star system in the zodiac constellation of Pisces. With an apparent visual magnitude of 6.04, it is near the lower limit of visibility to the naked eye under good seeing conditions. An annual parallax shift of 27.36 mas as measured from Earth's orbit provides a distance estimate of 199 light years. It has a relatively high proper motion, traversing the celestial sphere at a rate of 0.208 arcseconds per year, and is moving closer to the Sun with a heliocentric radial velocity of −10 km/s.
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17 Crateris is a wide binary star system in the equatorial constellation of Hydra, located 90.5 light years away from the Sun. It is visible to the naked eye as a faint, yellow-white hued star with a combined apparent visual magnitude of 4.93. The system is traversing the celestial sphere with a relative proper motion of /y, and is moving away from the Earth with a heliocentric radial velocity of +5.8 km/s. The dual nature of this system was discovered by W. Herschel in 1783, when they showed an angular separation of .
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Tau2 Hydrae is a probable astrometric binary star system in the equatorial constellation of Hydra. Based upon an annual parallax shift of 6.30 mas as seen from Earth, it is located around 520 light years from the Sun. The brighter component is visible to the naked eye with an apparent visual magnitude of +4.56. The primary member, component A, is an A-type main sequence star with a stellar classification of A3 V. It is a suspected variable of unknown type, with an amplitude of 0.06 in visual magnitude.
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XX Pyxidis is a star located in the constellation Pyxis. It is one of the more-studied members of a class of stars known as Delta Scuti variables—short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. Astronomers made more sense of its pulsations when it became clear that it is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85 ± 0.05 times as massive as the Sun.
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Two more distant encounters were with Sirius and Ross 614. None of these encounters are thought to have been close enough to affect the circumstellar disk orbiting Epsilon Eridani. Epsilon Eridani made its closest approach to the Sun about 105,000 years ago, when they were separated by . Based upon a simulation of close encounters with nearby stars, the binary star system Luyten 726-8, which includes the variable star UV Ceti, will encounter Epsilon Eridani in approximately 31,500 years at a minimum distance of about 0.9 ly (0.29 parsecs).
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Struve 2398 (Gliese 725) is a binary star system in the northern constellation of Draco. Struve 2398 is star number 2398 in the Struve Double Star Catalog of Baltic-German astronomer Friedrich Georg Wilhelm von Struve. The astronomer's surname, and hence the star identifier, is sometimes indicated by a Greek sigma, Σ. Although the components are too faint to be viewed with the naked eye, this star system is among the closest to the Sun. Parallax measurements by the Hipparcos spacecraft give them an estimated distance of about 11.6 light years away.
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This binary star system consists of a red giant (Mira, designated Mira A) undergoing mass loss and a high temperature white dwarf companion (Mira B) that is accreting mass from the primary. Such an arrangement of stars is known as a symbiotic system and this is the closest such symbiotic pair to the Sun. Examination of this system by the Chandra X-ray Observatory shows a direct mass exchange along a bridge of matter from the primary to the white dwarf. The two stars are currently separated by about 70 astronomical units.
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T Vulpeculae is a possible binary star system in the northern constellation of Vulpecula, near the star Zeta Cygni, close to the pair 31 Vulpeculae and 32 Vulpeculae. It is visible to the naked eye with an apparent visual magnitude that ranges around 5.75. The distance to this system is around 1,900 light years, as determined from its annual parallax shift of . A well-studied Classical Cepheid variable and one of the brightest known, the apparent magnitude of T Vulpeculae ranges from 5.41 to 6.09 over a period of 4.435 days.
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AMBER and PIONIER interferometry has shown that HR Carinae is a binary star system. The orbit is only weakly constrained but the most likely orbit has a semi-major axis of 3.3 mas, eccentricity of 0.4, and a period of 12.5 years. The possible orbits vary from nearly circular orbits of just a few years to highly eccentric orbits of several hundred years, all with the closest separation of the two stars at about 2 mas. The companion appears to be larger than the primary LBV star, but much less bright.
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A U Geminorum-type variable star or dwarf nova is a type of cataclysmic variable star consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from a cool main sequence or subgiant companion. V392 Persei was discovered in 1970 and received its variable star designation a year later. It is normally visual magnitude 17.4 and experiences outbursts of 2-3 magnitudes. Its spectrum in the quiescent state has been studied and only the cool star is detected.
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Antlia is a faint constellation; its brightest star is Alpha Antliae, an orange giant that is a suspected variable star, ranging between apparent magnitudes 4.22 and 4.29. S Antliae is an eclipsing binary star system, changing in brightness as one star passes in front of the other. Sharing a common envelope, the stars are so close they will one day merge to form a single star. Two star systems with known exoplanets, HD 93083 and WASP-66, lie within Antlia, as do NGC 2997, a spiral galaxy, and the Antlia Dwarf Galaxy.
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Mu Cassiopeiae (μ Cassiopeiae, abbreviated μ Cas) is a binary star system in the constellation Cassiopeia. This system shares the name Marfak with Theta Cassiopeiae, and the name was from Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". Mu Cassiopeiae is given as a standard star for the spectral class G5Vb, although it is frequently described as a subdwarf, meaning it has a luminosity below that expected for a G5 main sequence star. There are five visible companions to Mu Cassiopeiae listed in the Washington Double Star Catalog.
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The separate components can be resolved with the naked eye. The fifth-brightest star is Zeta Apodis at magnitude 4.8, a star that has swollen and cooled to become an orange giant of spectral type K1III, with a surface temperature of 4649 K and a luminosity 133 times that of the Sun. It is 300 ± 4 light-years distant. Near Zeta is Iota Apodis, a binary star system 1,040 ± 60 light-years distant, that is composed of two blue-white main sequence stars that orbit each other every 59.32 years.
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This is a confirmed member of the Scorpius-Centaurus Association, which is a group of stars with similar ages, locations, and trajectories through space, implying that they formed together in the same molecular cloud. Beta Muscae is considered a runaway star system as it has a high peculiar velocity of relative to the normal galactic rotation. Runaway stars can be produced through several means, such as through an encounter with another binary star system. Binary systems form a relatively small fraction of the total population of runaway stars.
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HD 128429 is a binary star system located at a distance of 88 light years from the Sun in the southern zodiac constellation of Libra. It has a yellow-white hue and is just barely visible to the naked eye with an apparent visual magnitude of 6.20. The system is drifting closer to the Sun with a radial velocity of −66 km/s and has a high proper motion, traversing the celestial sphere at the rate of per year. It is a high velocity star system with a net heliocentric velocity of 158.8 km/s.
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IM Pegasi is a variable binary star system approximately 329 light-years away in the constellation of Pegasus. With an apparent magnitude of 5.7, it is visible to the naked eye. Increased public awareness of it is due to its use as the guide star for the Gravity Probe B general relativity experiment. It was chosen for this purpose because its microwave radio emissions are observable with a large radio telescope network on the ground in such a manner that its precise position can be related by interferometry to distant quasars.
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The light curve saw two maxima a few months after the outburst, along with strong oscillations. Today its brightness is visual magnitude 15.5. This is a close binary star system consisting of a white dwarf with 93% of the Sun's mass – the source for the nova explosion – and a lower mass red dwarf companion from which the white dwarf is accreting matter. The system is located approximately 4,500 light years from the Sun based on parallax, with its visual magnitude being diminished by an extinction of due to interstellar dust.
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In 2008 a study was undertaken of fourteen stars with exoplanets that were originally discovered using the transit method through relatively small telescopes. These systems were re-examined with the reflector telescope at the Calar Alto Observatory in Spain. This star system, along with two others, was determined to be a previously unknown binary star system. The previously unknown secondary star is a dim magnitude 15 M-type star separated by about 111 AU from the primary, appearing offset from the primary by about one arc second in the images.
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Epsilon Telescopii is a binary star system: the brighter component, Epsilon Telescopii A, is an orange giant of spectral type K0III with an apparent magnitude of +4.52, while the 13th magnitude companion, Epsilon Telescopii B, is 21 arcseconds away from the primary, and just visible with a 15 cm aperture telescope on a dark night. The system is 417 light-years away. Iota Telescopii and HD 169405—magnitude 5 orange giants of spectral types K0III and K0.5III respectively—make up the quartet. They are around 370 and 497 light-years away from the Sun respectively.
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HR 5401 is a possible astrometric binary star system in the southern constellation of Lupus. With an apparent visual magnitude of 5.83, it is just visible to the naked eye under good seeing conditions. The distance to HR 5401 can be estimated from its annual parallax shift of , yielding a range of 205 light years. It is moving closer to Earth with a heliocentric radial velocity of −30 km/s, and is expected to come within in ~524,000 years. This is an Am star with a stellar classification of A1m A5/7-F2.
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The orbital separation is only known approximately, with a semi-major axis of 15–16 AU. The orbit is highly eccentric, e = 0.9. This means that the separation of the stars varies from around 1.6 AU, similar to the distance of Mars from the Sun, to 30 AU, similar to the distance of Neptune. Perhaps the most valuable use of an accurate orbit for a binary star system is to directly calculate the masses of the stars. This requires the dimensions and inclination of the orbit to be accurately known.
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NGC 3603-A1 (HD 97950A1) is a double-eclipsing binary star system located at the centre of the HD 97950 cluster in the NGC 3603 star-forming region, about 25,000 light years from Earth. Both stars are of spectral type WN6h and among the most luminous and most massive known. HD 97950 was catalogued as a star, but was known to be a dense cluster or close multiple star. In 1926, the six brightest members were given letters from A to F, although several of them have since been resolved into more than one star.
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The radial velocity of a star away from or towards the observer can be determined by measuring the red shift or blue shift of its spectrum. The American astronomer Vesto Slipher made a series of such measurements from 1902 to 1904 and discovered that the radial velocity of α Andromedae varied periodically. He concluded that it was in orbit in a spectroscopic binary star system with a period of about 100 days. A preliminary orbit was published by Hans Ludendorff in 1907, and a more precise orbit was later published by Robert Horace Baker.
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Zeta Crateris (ζ Crateris) is a probable binary star system in the southern constellation of Crater. Zeta Crateris appears to be about half-way between Epsilon Corvi to the southeast and Beta Crateris to the northwest, and marks the lower left corner of the rim of the bowl. Eta Crateris lies somewhat less than half of the way from Zeta Crateris to Gamma Corvi, the bright star above, (north) of Epsilon Corvi. Zeta Crateris is a photometrically constant system that is visible to the naked eye with an apparent visual magnitude of 4.740.
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40 Cancri is a binary star system in the zodiac constellation of Cancer, located about 614 light years from the Sun in the Beehive Cluster (NGC 2632). It is a challenge to view with the naked eye, having an apparent visual magnitude of 6.61. The system is moving further from the Earth with a heliocentric radial velocity of 34 km/s. The primary component appears to be a normal A-type main-sequence star with a stellar classification of A1 V, showing neither an organized magnetic field nor a chemical peculiarity.
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However, it has an excessive temperature for its luminosity, and thus is considered an extreme blue straggler. This is a second generation star formed through a collision of two low mass stars some 5–350 million years ago. The collision was either between two separate cluster members or the coalescence of a binary star system. With an effective temperature of 9,382 K, this is the hottest star in the cluster by about 1,200 K. It has 2.46 times the mass of the Sun and 2.72 times the Sun's radius.
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HD 142022 is a binary star system located in the southernmost constellation of Octans. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.70. The distance to this system is 112 light years based on parallax, but it is drifting closer to the Sun with a radial velocity of −9.6 km/s. The primary, designated component A, is an old, Population I G-type star with a stellar classification of G9IV-V, showing a spectrum with mixed traits of a main sequence and a subgiant star.
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Epsilon Canis Minoris (ε Canis Minoris) is a suspected binary star system in the equatorial constellation of Canis Minor. It is a fifth magnitude star, which means it is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of just 3.13 mas as seen from Earth, this star is located roughly 770 light years from the Sun, give or take a 40 light year margin of error. This is an evolved G-type bright giant star with a stellar classification of G6.5 IIb.
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This is an evolved giant star with a stellar classification of K1 III. It has a mild barium anomaly, which may indicate this is a binary star system with a white dwarf companion. The interferometry-measured angular diameter of the visible component is about , which, at its estimated distance, equates to a physical radius of about 44 times the radius of the Sun. This star has four times the mass of the Sun and is radiating 761 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,370 K.
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67 Cancri is a wide binary star system in the zodiac constellation of Cancer, located 195 light years away from the Sun. It is just visible to the naked eye as a faint, white-hued star with a combined apparent magnitude of 6.07. The binary nature of this system was discovered by James South and John Herschel. As of 2007, the two components have an angular separation of , corresponding to a projected separation of . They are moving further from the Earth with a heliocentric radial velocity of +12 km/s.
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61 Cancri (61 Cnc) is the Flamsteed designation for a visual binary star system in the northern constellation Cancer. The pair have a combined apparent magnitude of 6.25, which means 61 Cancri is faintly visible to the naked eye. (According to the Bortle scale, it can be seen from rural or even dark suburban skies.) Based upon parallax measurements, the system is approximately 181 light years away from Earth. The two components appear to be roughly identical with individual masses of about 1.4 times that of the Sun and apparent magnitudes of 7.0.
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Chi Cancri, Latinized from χ Cancri, is a candidate astrometric binary star system in the northern zodiac constellation of Cancer. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.14. The system is located at a distance of 59 light years from the Sun, based on parallax, and is drifting further away with a radial velocity of +33 km/s. It is estimated to have made its closest approach some 274,000 years ago when it came to within .
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GG Tauri, often abbreviated as GG Tau, is a quadruple or quintuple star system in the constellation Taurus. At a distance of about 450 light years (140 parsecs) away, it is located within the Taurus-Auriga Star Forming Region. The system comprises two (possibly three) stars orbiting each other in a hierarchical triple system, and another binary star system more distant from the central system. The system is unusual because it contains two distinct circumstellar disks: one surrounding the entire system, and another surrounding the primary component of the system.
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The variability of this system was discovered from photographic plates in 1935. It is a binary star system with an orbital plane that is nearly aligned with the line of sight to the Earth. Once every 2.1781542 day orbit, each of the closely orbiting stars eclipses its partner, causing a net magnitude drop to 9.4 during the primary eclipse and to magnitude 9.1 when the secondary component is eclipsed. The secondary member covers 51% of the larger star during the primary eclipse, while the primary covers 88% of the secondary.
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11 Comae Berenices is a binary star system in the northern constellation of Coma Berenices, located in the sky, east and slightly north of Denebola in Leo, but not nearly as far east as ε Virginis in Virgo. It is about a degree from the elliptical galaxy M85 and two degrees north of the spiral galaxy M100. Based upon an annual parallax shift of , the star is located 305 light years away from the Sun. It is visible to the naked eye as a faint, orange- hued star with an apparent visual magnitude of 4.72.
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This widely believed prediction has been occasionally tested using astronomical observations. For example, in a binary star system, the two stars are moving in opposite directions, and one might test the prediction by analyzing their light. (See, for instance, the De Sitter double star experiment.) Unfortunately, the extinction length of light in space nullifies the results of any such experiments using visible light, especially when taking account of the thick cloud of stationary gas surrounding such stars. However, experiments using X-rays emitted by binary pulsars, with much longer extinction length, have been successful.
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This is a spectroscopic binary, which is a type of binary star system in which the two stars are so close together that they have not been individually resolved with a telescope. The pair orbit each other with a period of about 196 days and an eccentricity of nearly 0.5. The combined spectrum of this pair matches a star with a stellar classification of B1.5 III. The 'III' luminosity class indicates the presence of a giant star that has exhausted the supply of hydrogen at its core and is in a late evolutionary stage.
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HR 6594 is the Bright Star Catalogue designation for a binary star system in the northern constellation of Hercules. It is faintly visible to the naked eye with an apparent visual magnitude of 5.55; according to the Bortle scale, it is sufficiently bright to be visible from dark suburban skies. The distance to this system, as determined using parallax measurements, is about 114 light years. On the celestial sphere it is located near the star Alpha Ophiuchi; their projected separation is just 3 light years, although their actual separation is much greater.
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Eta Tucanae, Latinized from η Tucanae, is a probable binary star system in the southern constellation of Tucana, a few degrees to the north of Epsilon Tucanae. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of +5.00. parallax measurements provide a distance estimate of about 154 light years from the Sun, and it is drifting further away with a mean radial velocity of +32.5 km/s. It is a member of the 30 million year old Tucana-Horologium association of co-moving stars.
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84 Ceti is the Flamsteed designation for a binary star system in the equatorial constellation of Cetus. It has an apparent visual magnitude of 5.7, making it faintly visible to the naked eye from dark suburban skies. Parallax measurements with the Hipparcos spacecraft put this system at a distance of around 74 light years. The primary, 84 Ceti A, is an F-type main sequence star with a stellar classification of F7V. It is slightly larger than the Sun, with 117% of the Sun's mass, 121% of the radius, and 213% of the luminosity.
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HD 9578 is a candidate wide binary star system located at a distance of approximately 183 light-years from the Sun in the southern constellation of Sculptor. The main star must be viewed with binoculars or a telescope, as its low apparent visual magnitude of 8.35 is too faint to be viewed with the naked eye. The system is drifting closer to the Sun with a radial velocity of −4 km/s. The primary component is an ordinary G-type main-sequence star with a stellar classification of G1V.
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S Coronae Australis (S CrA), is a young binary star system estimated to be around 2 million years old located in the constellation Corona Australis. It is composed of a G-type main sequence star that is about as luminous as and just over twice as massive as the Sun, and a smaller K-type main sequence star that has around 50-60% of the Sun's luminosity and 1.3 times its mass. Both stars are T Tauri stars and both show evidence of having circumstellar disks. The system is around 140 parsecs distant.
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However, the measurement of pulsations is very difficult, given the scarcity of variable blue stragglers, the small photometric amplitudes of their pulsations and the crowded fields in which these stars are often found. Some blue stragglers have been observed to rotate quickly, with one example in 47 Tucanae observed to rotate 75 times faster than the Sun, which is consistent with formation by collision. The other explanation relies on mass transfer between two stars born in a binary star system. The more massive of the two stars in the system will evolve first and as it expands, will overflow its Roche lobe.
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5 Serpentis is a wide binary star system in Serpens Caput, the western section of the equatorial constellation of Serpens. It is faintly visible to the naked eye with an apparent visual magnitude of 5.10. Based upon an annual parallax shift of as viewed from Earth's orbit, it is located 83 light years away. The brighter member is an IAU radial velocity standard star, and it is moving away from the Sun with a heliocentric radial velocity of +54.3 km/s. The system made its closest approach to the Sun about 153,000 years ago at a separation of .
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Chi1 Sagittarii (χ1 Sagittarii) is a binary star system in the zodiac constellation of Sagittarius. The pair have a combined apparent visual magnitude of +5.03, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 12.95 mas as seen from Earth, it is located around 252 light years from the Sun. It is advancing through space in the general direction of the Earth with a radial velocity of −43.4 km/s. This is a visual binary with an orbital period of 5.72 years, an eccentricity of 0.710, and an angular semimajor axis of 69 mas.
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Kappa Velorum (κ Velorum, abbreviated Kappa Vel, κ Vel; formally named Markeb ) is a binary star system in the southern constellation of Vela. The two components are designated Kappa Velorum A and B. From parallax measurements, this system is located at a distance of roughly from the Sun. The apparent visual magnitude is 2.48, making it readily visible to the naked eye in the southern hemisphere. It forms part of an asterism known as the False Cross along with Delta Velorum, Iota Carinae and Epsilon Carinae, so called because it is sometimes mistaken for the Southern Cross, causing errors in astronavigation.
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Epsilon Ursae Minoris (ε Ursae Minoris) is a binary star system in the northern circumpolar constellation of Ursa Minor. It is visible to the naked eye with a combined apparent visual magnitude of 4.19. Based upon an annual parallax shift of 10.73 mas as seen from the Earth, it is located around 300 light years from the Sun. The pair are drawing nearer to the Sun with a radial velocity of −10.57 km/s. This system forms a detached, single-lined spectroscopic binary with an orbital period of 39.5 days and a low eccentricity of 0.04.
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64 Piscium is the Flamsteed designation for a close binary star system in the zodiac constellation of Pisces. It can be viewed with the naked eye, with the components having a combined apparent visual magnitude of 5.07. An annual parallax shift of 42.64 mas provides a distance estimate of 46.5 light years. The system is moving further from the Sun with a radial velocity of +3.76 km/s. This is a double-lined spectroscopic binary system consisting of two similar components designated Aa and Ab. The initial orbital elements were determined by Abt and Levy (1976), giving an orbital period of 13.8 days.
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Binary star systems are common, found more frequently than single star systems like our own. The arrangement of HD 113766, a binary star system with a protoplanetary disk around one star, is somewhat similar to the one-half of the system HD 98800, which has been reported to have a large amount of warm dust mass at the equivalent distance of the solar system's asteroid belt. It is not currently known why both of these star systems should have such configurations; i.e. a protoplanetary disk around part of the system while other stars in the system lack one.
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The Struve–Sahade effect (S–S effect) occurs in a double-lined spectroscopic binary star system when the strength of the spectral lines of the components varies during the orbital motion. A spectroscopic binary is called double- lined when the absorption lines of both stars can be observed with a spectroscope. As each member of the star system approaches the observer in turn, the absorption lines of that star are shifted toward the blue end of the optical spectrum by the Doppler effect. Likewise, as a star moves away, its lines are shifted toward the red end of the spectrum.
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The X-ray continuum can arise from bremsstrahlung, black-body radiation, synchrotron radiation, or what is called inverse Compton scattering of lower-energy photons by relativistic electrons, knock-on collisions of fast protons with atomic electrons, and atomic recombination, with or without additional electron transitions. An intermediate-mass X-ray binary (IMXB) is a binary star system where one of the components is a neutron star or a black hole. The other component is an intermediate mass star. Hercules X-1 is composed of a neutron star accreting matter from a normal star (HZ Herculis) probably due to Roche lobe overflow.
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This is a wide binary star system and may even be a triple star. The two visible components orbit each other with a preliminary estimated period of 258 years and a large eccentricity of 0.931. As of 2014, the visible components have an angular separation of 0.80 arc seconds on a position angle of 359°. The primary star, component A, is a B-type subgiant star with a stellar classification of B5 VI. Based upon isochrone curve fitting it is hypothesized to be a pair of matching B5 stars, and is a Be variable with an uncertain maximum.
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Position measurements of the pair made with the Hipparcos spacecraft show an annual parallax shift of 0.0935 seconds of arc, which is equivalent to a distance of about from the Sun. It is a binary star system with an angular separation of 4.0 arcseconds. Both members are pre-main sequence, red dwarf stars and are among the youngest of this type in the neighborhood of the Sun. Relative to the Sun, component A has about 27% of the mass and 3.6% of the luminosity, while component B has 25% of the mass and 3.3% of the luminosity.
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HD 240429 (nicknamed Krios) and HD 240430 (Kronos) is a wide binary star system in the constellation of Cassiopeia. Both components of the system are yellow G-type main-sequence stars. HD 240430 is a Sun-like star in appearance, but it seems to have eaten its own planets, for which it is given the nickname Kronos, after the Greek god and the leader of the first generation of Titans. Its unusual properties were described by a team of astrophysicists at Princeton University in 2017, led by Semyeong Oh. Kronos and Krios are about 350 light years away from Earth.
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Phi Piscium (Phi Psc, φ Piscium, φ Psc) is a binary star system approximately 380 light years away in the constellation Pisces. It consists of Phi Piscium A, with a spectral type of K0III, and Phi Piscium B. Phi Piscium A possesses a surface temperature of 3,500 to 5,000 kelvins. Some suggest the only visible companion in the Phi Piscium B sub-system is a late F dwarf star, while others suggest it is a K0 star. The invisible component of the Phi Piscium B sub- system is proposed to have a spectral type of M2V.
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The two stars are located at similar distances from the Sun and share the same motion through space, confirming that they are gravitationally bound and form a wide binary star system. They have an angular separation of 309.2 arc seconds (5.2 arc minutes); far enough apart to appear as a close pair of separate stars to the naked eye under suitable viewing conditions. The distance between the two stars is at least 3,750 AU, so their orbital period is 170,000 years or more. Both stars share similar physical characteristics to the Sun, so they are considered solar analogs.
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Infrared observations show a huge region of dust surrounds the planetary nebula, spanning . The combined mass of the gas and dust is estimated at The nebula originated from a binary star system with the designation HD 281679 from the Henry Draper Catalogue. The bright, visible component is a giant star on the horizontal branch with a stellar classification of A0III, while the nebula-generating companion is now a hot, sub-luminous O-type star. During the formation of the nebula, the pair shared a common envelope and had an orbital period of around 4–9 days.
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Also known as Altarf or Tarf, Beta Cancri is the brightest star in Cancer at apparent magnitude 3.5. Located 290 ± 30 light-years from Earth, it is a binary star system, its main component an orange giant of spectral type K4III that is varies slightly from a baseline magnitude of 3.53—dipping by 0.005 magnitude over a period of 6 days. An aging star, it has expanded to around 50 times the Sun's diameter and shines with 660 times its luminosity. It has a faint magnitude 14 red dwarf companion located 29 arcseconds away that takes 76,000 years to complete an orbit.
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The Blue Moon is covered in life-giving water and an atmosphere so dense that enormous creatures hypothetically can take flight. The Blue Moon orbits a Water Cloud Jovian planet (a Jupiter-like planet that is cool enough to have visible rain clouds in its atmosphere) orbiting a close binary star system. The Blue Moon itself is roughly an earth mass but has an air pressure around three times that of Earth's at sea level. A distinguishing feature of Blue Moon is that it has no polar ice caps: the thick atmosphere keeps temperatures constant across the moon's surface.
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DG Canum Venaticorum is the variable star designation for a binary star system in the northern constellation of Canes Venatici. As of 2009, the pair have an angular separation of 0.20″ along a position angle of 285°, which corresponds to a physical separation of around 3.6 AU. With an apparent visual magnitude of 12.02, the pair are much too faint to be seen with the naked eye. Parallax measurements place the system at a distance of roughly 59 light years from the Earth. The stellar classification of the primary component is M4.0Ve, indicating it is a red dwarf with emission lines present.
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Gamma Piscis Austrini (γ Piscis Austrini) is binary star system in the southern constellation of Piscis Austrinus. It is visible to the naked eye with a combined apparent visual magnitude of +4.448. As of 2010, the pair had an angular separation of 4 arc seconds along a position angle of 255°. Based upon an annual parallax shift of 15.14 mas as seen from the Earth, the system is located about 215 light years from the Sun. The magnitude 4.59 primary, component A, is a white-hued, chemically peculiar A-type main sequence star with a stellar classification of .
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3 Vulpeculae (abbreviated 3 Vul) is a binary star system in the northern constellation of Vulpecula, located around 360 light years away from the Sun. 3 Vulpeculae is its Flamsteed designation. It has been nicknamed "the Observer's Nightmare" (or its Latin free translation, "Spectatori Error Inextricabilis") by some astronomers because it is difficult to study as its orbital period is close to a year and it is pulsating with a period close to a day. It is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 5.18.
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It is an estimated 2.5 billion years old and is spinning with a projected rotational velocity of 10 km/s. The star has 1.25 times the mass of the Sun and 1.4 times the Sun's radius. It is radiating 2.9 times the luminosity of the Sun from its photosphere at an effective temperature of 6,338 K. A magnitude 11.5 companion star was detected in 1894 making this a binary star system. The binary companion was confirmed to be gravitationally bound in 2007 and determined to be a red dwarf of spectral type K8.5-M1.5 with 54% of the Sun's mass.
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This is a single-lined spectroscopic binary star system with an orbital period of 69.92 days and an eccentricity of 0.30. The visible component has the spectrum of an evolved, B-type giant star with a stellar classification of B8 III. It is a helium-weak star, a type of chemically peculiar star that displays abnormally weak absorption lines of helium for a star of its temperature. Omega Cassiopeiae has an estimated 4.7 times the mass of the Sun and is radiating 488 times the Sun's luminosity from its photosphere at an effective temperature of around 12,737 K.
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It is advancing in the general direction of the Sun with a radial velocity of roughly −10.6 km/s. This is a single-lined spectroscopic binary star system with an orbital period of 940.2 days and an eccentricity of 0.4. The visible component has the spectrum of a B-type main-sequence star with a stellar classification of B2.5 V. It has an estimated 10.1 times the mass of the Sun and around 4.5 times the Sun's radius. At the age of 19 million years, it has a high rate of rotation with a projected rotational velocity of about 139 km/s.
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Psi Cassiopeiae (ψ Cassiopeiae) is a binary star system in the northern constellation of Cassiopeia. The primary component, ψ Cassiopeiae A, is an orange K-type giant with an apparent magnitude of +5.0; it is a double star, designated CCDM J01259+6808AB, with a fourteenth magnitude star (component B) located 3 arcseconds from the primary. Located about 25 arcseconds distant there is a 9.8 magnitude optical companion CCDM J01259+6808CD, designated ψ Cassiopeiae B in older star catalogues, which is itself another double; CD comprises a 9.4 magnitude component C and a 10 magnitude component D.
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Rho Centauri, Latinized from ρ Centauri, is a binary star system in the southern constellation of Centaurus. It is visible to the naked eye as a blue- white hued point of light with a combined apparent visual magnitude of +3.97. The system is located approximately 276 light years from the Sun based on parallax, and is drifting further away with a radial velocity of around +15 km/s. It is a proper motion member of the Lower-Centaurus Crux sub-group in the Scorpius-Centaurus OB association, the nearest such association of co- moving massive stars to the Sun.
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SDSS J0018−0939 was identified as a star likely to have a very low amount of metals. Many other metal-poor stars have been identified in dwarf galaxies around the Milky Way. Most of the metal-poor stars are not as metal-poor as SDSS J001−0939 and do not share other SDSS J0018−0939 properties, suggesting that the origin of these metal-poor stars is different than the origin of SDSS J0018−0939. SDSS J0018−0939 has no signature of the extra mixing or mass transfer across a binary star system, which would have changed its chemical composition.
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This is a spectroscopic binary star system with an orbital period of 116.8 years and an eccentricity of 0.56. In 2010, speckle interferometry observations showed an angular separation of between the two components along a position angle of . The primary is a G-type main sequence star with a spectral classification of G1 V. It has about 35% more mass than the Sun and shines six times as brightly from an outer atmosphere that has an effective temperature of 5940 K. The system is roughly 3.7 billion years old and is a member of the galactic thin disk population.
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HD 172044 and BD+33°3154B are two components of a binary star system in the constellation Lyra, approximately 520 light years away from Earth. 5th magnitude HD 172044 is a giant or subgiant star with the spectral type B8II- IIIp... The "p..." signifies that the star has a peculiar spectrum and spectral peculiarities have yet to be described. It is bluish white in color and has a surface temperature of 11,000 to 25,000 kelvins. It is therefore at least twice as hot as our Sun on its surface, and many times brighter and larger in size.
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It is the gravesite of Darth Vader. The moon orbits Tana—the Ewokese word for Endor's host planet—a gas giant located in the Endor system, a binary star system positioned in the Moddell sector of the galaxy's Outer Rim Territories."Star Wars:Absolutely Everything You Need to Know""Star Wars: Galactic Atlas" Located in grid square H-16 on the Standard Galactic Grid, it was connected to Cerea and Bakura by a hyperspace route."Star Wars: Beginner Game" The planet was orbited by nine moons, the largest of which was known as the Forest Moon of Endor or "Sanctuary Moon".
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The binary nature of the star at the centre of the nebula was discovered in 2014, when a study of why the nebula was not regular was conducted, resolving the previously thought single star into a double star. The two white dwarf stars forming the binary star system at the heart of the nebula orbit each other with a period of about 4 hours. The two stars have a combined mass of about 1.8 solar masses, with each star being slightly less massive than the Sun. As of 2015, they are the most massive binary double white dwarf star system known.
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Alpha Ophiuchi is a binary star system with an orbital period of about 8.62 years. The orbital parameters were only poorly known until 2011 when observations using adaptive optics produced a better orbital fit, allowing the individual masses of the two components to be determined. The primary component, Alpha Ophiuchi A, has a mass of about 2.4 times the mass of the Sun, while the secondary, Alpha Ophiuchi B, has 0.85 solar masses. Estimates of the mass of the primary by other means range from a low of 1.92 to 2.10 solar masses, up to 2.84 or even 4.8 solar masses.
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The unusual characteristics of the event led to an immediate massive follow-up campaign by tens of professional and amateur observers over the next 500 days, during which 5 brightening events were closely observed. The star brightened up to two and a half magnitudes in each microlensing event over its baseline brightness. The brightenings were determined to have been caused by a dim binary star system much closer to the Earth, acting as a moving, changing gravitational lens. The light of the lens star system itself was lost in the glare of the brighter star 2MASS 19400112+3007533.
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At present it has ten times the Sun's radius. This is a red clump giant, which indicates it is on the horizontal branch and is generating energy through helium fusion at its core. It is around three billion years old with 1.5 times the mass of the Sun. The star is radiating fifty times the Sun's luminosity from its swollen photosphere at an effective temperature of 4,853 K. According to Eggleton and Tokovinin (2008), this is most likely a wide binary star system; the secondary companion is a magnitude 9.6 star at an angular separation of from the primary.
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Located near Alpha is Delta Antliae, a binary star, 450 ± 10 light-years distant from Earth. The primary is a blue- white main sequence star of spectral type B9.5V and magnitude 5.6, and the secondary is a yellow-white main sequence star of spectral type F9Ve and magnitude 9.6. Zeta Antliae is a wide optical double star. The brighter star—Zeta1 Antliae—is 410 ± 40 light-years distant and has a magnitude of 5.74, though it is a true binary star system composed of two white main sequence stars of magnitudes 6.20 and 7.01 that are separated by 8.042 arcseconds.
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The scenario created was that of a binary star system in the globular cluster, Messier 13, with an Earthlike planet called Troas (or more informally, "Junior") located at one of the system's Lagrangian points. An earlier expedition to Troas for colonization had suffered some mysterious disaster, and a second expedition is being sent to find out if "Junior" was suitable for colonization, and to find out what happened to the first expedition. Asimov finished his short story, and then Anderson finished a story called "Question and Answer", but Kidd (or James Blish) never completed the third story. The proposed book was never printed.
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Omega Lupi, Latinized from ω Lupi, is a double star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 4.33, showing up as a red-hued star just to the south of Gamma Lupi. Based upon an annual parallax shift of 8.97 mas as seen from Earth, it is located around 360 light years from the Sun. As of 2007, the components of this system had an angular separation of 11.4 arc seconds along a position angle of 29°, and are most likely gravitationally bound as a wide binary star system.
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This is a spectroscopic binary star system with an orbital period of around 3.6 years and an eccentricity of 0.5. It is classified as a probable (91% chance) eclipsing binary with the variable star designation UZ Lyn, showing a net magnitude decrease of 0.3 during an occultation. The primary component is an A-type main-sequence star with a stellar classification of A2 Vs, where the 's' indicates narrow (sharp) absorption lines. The orbiting companion may be the source of the X-ray emission from this system, as stars similar to the primary component do not generally produce detectable levels of X-rays.
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NGC 3603-C (HD 97950C) is a single-lined spectroscopic binary star system located at the centre of the HD 97950 cluster in the NGC 3603 star-forming region, about 25,000 light years from Earth. The primary has spectral type WN6h and is among the most luminous and most massive known. HD 97950 was catalogued as a star, but was known to be a dense cluster or close multiple star. In 1926, the six brightest members were given letters from A to F, although several of them have since been resolved into more than one star.
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TU Muscae is a remote binary star system made up of two hot luminous blue main sequence stars of spectral types O7.5V and O9.5V, with masses 23 and 15 times that of the Sun. The stars are so close that they are in contact with each other (overcontact binary) and are classed as a Beta Lyrae variable as their light varies from earth as they eclipse each other. The spectra indicate they are hot stars, with surface temperatures of roughly 37200 and 34700 K respectively. They are both still on the main sequence of star evolution, burning their core hydrogen.
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It can be seen with the naked eye, having an apparent visual magnitude of +4.07. Based upon an annual parallax shift of 20.11 mas as seen from the Earth, the star is about 162 light years from the Sun. This is an A-type main sequence star with a stellar classification of A1 V. Radial velocity variations indicate it may be a binary star system, but when the system was examined in the infrared, no companion was detected. Theta Capricorni has an estimated 2.24 times the mass of the Sun and around 2.7 times the Sun's radius.
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Ross 614 (V577 Monocerotis) is a red dwarf UV Ceti flare star and it is the primary member of a nearby binary star system in the constellation of Monoceros. This star has a magnitude of about 11, making it invisible to the unaided eye even though it is one of the stars nearest to the Sun. This system is among the closest to the Sun at an estimated distance of about 13.3 light years. Because this star is so close to the Earth it is often the subject of study, hence the large number of designations by which it is known.
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30 Vulpeculae is a binary star system in the northern constellation of Vulpecula, located mid-way between Epsilon Cygni and a diamond-shaped asterism in Delphinus. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.91. The system is located approximately 350 light years away from the Sun based on parallax, and is drifting further away with a mean radial velocity of +30 km/s. The system has a relatively high proper motion, traversing the celestial sphere at the rate of 0.186 arc seconds per annum.
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Hot subdwarfs, of spectral types O and B, also termed "extreme horizontal-branch stars" are an entirely different class of objects to cool subdwarfs. These stars represent a late stage in the evolution of some stars, caused when a red giant star loses its outer hydrogen layers before the core begins to fuse helium. The reasons why this premature mass loss occurs are unclear, but the interaction of stars in a binary star system is thought to be one of the main mechanisms. Single subdwarfs may be the result of a merger of two white dwarfs or gravitational influence from substellar companions.
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HD 16760 is a binary star system approximately 227 light-years away in the constellation Perseus. The primary star HD 16760 (HIP 12638) is a G-type main sequence star similar to our Sun. The secondary, HIP 12635 is 1.521 magnitudes fainter and located at a separation of 14.6 arcseconds from the primary, corresponding to a physical separation of at least 660 AU. Announced in July 2009, HD 16760 has been confirmed to have a substellar object orbiting it. Whether or not this object is a brown dwarf or an extrasolar planet is currently not understood.
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IC 348 south of Omicron Persei IC 348 is a star-forming region in the constellation Perseus located about 315 parsecs from the Sun. It consists of nebulosity and an associated 2-million-year-old cluster of roughly 400 stars within an angular diameter of 20″. The most massive stars in the cluster are the binary star system BD+31°643, which has a combined spectral class of B5. Based upon infrared observations using the Spitzer Space Telescope, about half of the stars in the cluster have a circumstellar disk, of which 60% are thick or primordial disks.
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HR 7955 is a binary star system in the northern circumpolar constellation of Cepheus, near the constellation border with Cygnus. It has a yellow-white hue and is faintly visible to the naked eye with a combined apparent visual magnitude of 4.51. The system is located at a distance of 89 light-years (27.3 parsecs) from the Sun, based on parallax. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.243 arc seconds per annum, and is drifting closer to the Sun with a radial velocity of -33 km/s.
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It has 3.55 times the mass of the Sun and radiates 255 times the solar luminosity from its outer atmosphere at an effective temperature of about 13,716 K. Phi Eridani may form a wide binary star system with a 9th magnitude star at lies an angular separation of 86″. This companion is a G-type main sequence star with a stellar classification of G2V. It may also have a physical association with the naked-eye star Eta Horologii. It is a member of the Tucana-Horologium association, a old group of stars that share a common motion through space.
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The known secondary, component B, is magnitude 12.00 and lies at an angular separation of 4.6 arc seconds from the primary along a position angle of 18°, as of 2013. In 2015, this component was resolved via interferometry into a binary star system with a separation of 0.22 arc seconds, corresponding to a projected separation of 3 AU. Both components, Ba and Bb, are likely red dwarfs roughly of class M3 with masses of about 25% the mass of the Sun. They have a tentative orbital period of around six years and a semimajor axis of 0.19 arc seconds.
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The cluster has a visual magnitude of 3.8 and spans an angular diameter of 20 arc minutes. The tidal radius of the cluster is and it has an estimated combined mass of 589 times the mass of the Sun. Based upon its estimated age and motion through space, it may be associated with the Gould Belt. It includes an Algol variable star, BD+36° 3317, discovered in 2007 from Spain: this is a spectroscopic binary star system that undergoes regular eclipses because the orbital plane is nearly aligned with the line of sight to the Earth.
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This dimming lasts 640–730 days. In addition to this eclipse, the system also has a low amplitude pulsation with a non-consistent period of around 66 days. Epsilon Aurigae's eclipsing companion has been subject to much debate since the object does not emit as much light as is expected for an object its size. As of 2008, the most popularly accepted model for this companion object is a binary star system surrounded by a massive, opaque disk of dust; theories speculating that the object is a large, semitransparent star or a black hole have since been discarded.
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A0620-00 (abbreviated from 1A 0620-00) is a binary star system in the constellation of Monoceros. A0620-00 consists of two objects. The first object is a K-type main-sequence star with a spectral type of K5 V. The second object cannot be seen, but based on its calculated mass of , it is too massive to be a neutron star and must therefore be a stellar-mass black hole. At a distance of about roughly away, this would make A0620-00 one of the nearest known black holes to the Solar System, closer than GRO J1655-40.
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HD 224635 and HD 224636 is a pair of stars comprising a binary star system in the constellation Andromeda. They are located approximately 94 light years away and they orbit each other every 717 years. The primary star is HD 224635, a magnitude 6.46 star (making it visible by the naked eye under very favourable conditions) with a spectral type F8 that is 1.19 times more massive than the Sun. The secondary star is the slightly fainter HD 224636, with an apparent visual magnitude of 6.72, a spectral type G1, and 1.13 times more massive than the Sun.
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NR Canis Majoris is a binary star system in the southern constellation of Canis Major, located to the east of Sirius and Gamma Canis Majoris near the constellation border with Puppis. It has a yellow-white hue and is dimly visible to the naked eye with a combined apparent visual magnitude that fluctuates around 5.60. It is located at a distance of approximately 297 light years from the Sun based on parallax. The system is drifting closer to the Sun with a radial velocity of −29 km/s, and in about three million years it is predicted to approach within .
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Stars shine intrinsically, but they can also reflect light. In a close binary star system polarimetry can be used to measure the light reflected from one star off another (and vice versa) and therefore also the geometric albedos of the two stars. This task has been accomplished for the two components of the Spica system, with the geometric albedo of Spica A and B being measured as 0.0361 and 0.0136 respectively. The geometric albedos of stars are in general small, for the Sun a value of 0.001 is expected, but for hotter of lower gravity (i.e.
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Y Sextantis (abbreviated as Y Sex) is a W Ursae Majoris variable eclipsing contact binary star system located roughly at 360 light years from the Sun, whose two component stars share a common outer layer. Because the two components share their outer layers as the components of W Ursae Majoris do, they have the same stellar classification, and are classified as yellow F-type main sequence dwarfs. The components take 0.419822800 days (roughly 10 hours) to revolve around common barycentre. Orbital period variations would suggest the presence of additional perturbing objects, one of them likely substellar.
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Stein 2051 (Gliese 169.1, G 175-034, LHS 26/27) is a nearby binary star system, containing a red dwarf (component A) and a degenerate star (white dwarf) (component B), located in constellation Camelopardalis at about 18 ly from Earth. Stein 2051 is the nearest (red dwarf + white dwarf) separate binary system (40 Eridani BC is located closer at 16.26 light-years, but it is a part of a triple star system). Stein 2051 B is the 6th nearest white dwarf after Sirius B, Procyon B, van Maanen's star, LP 145-141 and 40 Eridani B.
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HD 60803 is a binary star system in the equatorial constellation of Canis Minor, located less than a degree to the northwest of the prominent star Procyon. It has a yellow hue and is visible to the naked eye as a dim point of light with a combined apparent visual magnitude of 5.904. The distance to this system is 135 light years as determined using parallax measurements, and is drifting further away with a radial velocity of +4.6 km/s. The binary nature of this star system was first noted by O. C. Wilson and A. Skumanich in 1964.
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Kepler-14 is a binary star system, which means that it is actually composed of two gravitationally bound stars that orbit a common point in space. The system is composed of a primary star, Kepler-14A, and a dimmer companion star, Kepler-14B. When the stars were observed, while searching for the planet Kepler-14b, the angular separation of the binary system made it extremely difficult to note the dimmer companion star. The stars have such a wide orbit that it takes approximately 2800 years for each star to complete a revolution around the centroid. The two stars are located approximately 980 parsecs (3,196 light years) from Earth.
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Psi Pegasi, which is Latinized from ψ Pegasi, is a binary star system within the great square in the northern constellation of Pegasus. It has a red hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.66. This object is located at a distance of approximately 476 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −6.6 km/s. The orbital elements for this system were computed for the first time in 2004 based on interferometric observations, yielding an orbital period of roughly 55 years and an eccentricity of about 0.19.
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First noticed in 1991, it is thought to be a cannonball star, shot out of a star cluster and now moving rapidly through space directly away from the galactic disc. The WZ Sagittae-type dwarf nova DY Canis Minoris (also known as VSX J074727.6+065050) flared up to magnitude 11.4 over January and February 2008 before dropping eight magnitudes to around 19.5 over approximately 80 days. It is a remote binary star system where a white dwarf and low mass star orbit each other close enough for the former star to draw material off the latter and form an accretion disc. This material builds up until it erupts dramatically.
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This is a single-lined spectroscopic binary star system with an orbital period of 2.9 years and an eccentricity of 0.48. The primary member, component A, is an evolved bright giant with a stellar classification of kA5hF0mF5 II. This notation indicates the star's spectrum shows the calcium K lines of an A5 star, the hydrogen lines of an F0 star, and the metallic lines of an F5 star. It is an evolved Am star of the ρ Puppis type, a class of evolved stars showing the Am chemical peculiarities. It is located in the instability strip of the Hertzsprung–Russell diagram but is not thought to be variable.
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GJ 3991 (also known as Gliese 3991 and G 203-47) is a binary star system located 24.2 light-years away in the constellation Hercules. It consists of a Red dwarf star with 20-30% the mass of the Sun, and a White dwarf star roughly 50% the mass of the sun. The two components orbit each other in a tight orbit only 0.11 astronomical units from each other, with an orbital period of only 14.71 days. Due to their small separation, the two objects have never been visually resolved and are merely predicted from the radial velocity changes of GJ 3991 A, making the system a spectroscopic binary.
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Upsilon Draconis (υ Dra) is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye with an apparent visual magnitude of 4.83. Based upon an annual parallax shift of 9.48 mas as measured from Earth, it is located around 340 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.02 due to interstellar dust. In Chinese, (), meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of υ Draconis, ι Draconis, η Draconis, ζ Draconis, θ Draconis, 73 Draconis, γ Cephei and 23 Cassiopeiae.
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2 Vulpeculae is a binary star system in the northern constellation of Vulpecula, located around 1,800 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.43. 2 Vulpeculae is a double-lined spectroscopic binary; as of 2002, the pair had an angular separation of along a position angle of 127.2°. The primary component of the binary is a rapidly rotating Be star with a stellar classification of B1 IV. It is a variable star with an amplitude of 0.06 magnitude and a period of 0.6096 days, tentatively classified as Beta Cephei variable.
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56 Andromedae, abbreviated 56 And, is a probable binary star system in the northern constellation of Andromeda. 56 Andromedae is the Flamsteed designation. It has a combined apparent visual magnitude of 5.69, which is just bright enough to be dimly visible to the naked eye under good seeing conditions. The distance to this system can be ascertained from its annual parallax shift, measured at with the Gaia space observatory, which yields a separation of 330 light years. It is moving further from the Earth with a heliocentric radial velocity of +62 km/s and is traversing the celestial sphere at a relatively high rate of per year.
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The orbit of 16 Cygni Bb (black) compared to the inner planets in the Solar System. Unlike the planets in the Solar System, the planet's orbit is highly elliptical, and its distance varies from 0.54 AU at periastron to 2.8 AU at apastron. This high eccentricity may have been caused by tidal interactions in the binary star system, and the planet's orbit may vary chaotically between low and high-eccentricity states over a period of tens of millions of years. Preliminary astrometric measurements in 2001 suggested the orbit of 16 Cygni Bb may be highly inclined with respect to our line of sight (at around 173°).
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51 Andromedae, abbreviated 51 And and formally named Nembus , is the 5th brightest star in the northern constellation of Andromeda, very slightly dimmer than the Andromeda Galaxy also being of 4th magnitude. It is an orange K-type giant star with an apparent magnitude of +3.59 and is about 169 light- years from the Earth/solar system. It is traditionally depicted as one of the two northern, far upper ends of the mythological, chained-to-the-rocks princess, the other being binary star system Gamma Andromedae. At an estimated age of 1.7 billion years, this is an evolved red giant star with a stellar classification of .
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According to the Return of the Jedi novelization, the planet disappeared in an ancient cataclysm. The Ewok television films depict a gas giant in the sky, and novels such as The Truce at Bakura and Dark Apprentice also mention a planet visible from the moon. The planet is called "Tana" in the Ewoks animated series, which also depicts a binary star system (while other sources depict only one sun). In a Star Wars Tales comic entitled Apocalypse Endor, an Imperial veteran of Endor refers to the moon being devastated by the impact of falling debris from the Death Star, which was blown up while in orbit around the moon.
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UX Tauri, abbreviated as UX Tau, is a binary star system approximately 450 light-years away in the constellation of Taurus (the Bull). It is notable for the fact that, despite its recent (in stellar terms) creation, the Spitzer Space Telescope discovered that its protoplanetary disk contains a gap. The dust, which normally accumulates in an expanding ring starting right next to the star at such a young age, is either very thin or nonexistent at a range of 0.2 to 56 AU from the star. Typically, this means that the early ancestors of planets may be forming from the disk, though the star only ignited about 1 million years ago.
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After a fatal car accident on Earth, Herb Asher is placed into cryonic suspension as he waits for a spleen replacement. Clinically dead, Herb experiences lucid dreams while in suspended animation and relives the last six years of his life. In the past, Herb lived as a recluse in an isolated dome on a remote planet in the binary star system, CY30-CY30B. Yah, a local divinity of the planet in exile from Earth, appears to Herb in a vision as a burning flame, and forces him to contact his sick female neighbor, Rybys Rommey, who happens to be terminally ill with multiple sclerosis and pregnant with Yah's child.
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12 Lacertae is a wide binary star system in the northern constellation of Lacerta, located roughly 1,090 light years away from the Sun based on parallax. It is visible to the naked eye as a dim, blue-white hued point of light with a baseline apparent visual magnitude of 5.23. The system is drifting closer to the Earth with a mean heliocentric radial velocity of –12.5. It is a probable member of the I Lacertae OB association (Lac OB1). The primary component is a Beta Cephei variable with a stellar classification of B1.5III, matching a B-type star with the luminosity class of a giant star.
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Based upon the age and direction of motion of this star, it is a member of the Upper Scorpius sub-group of the Scorpius-Centaurus Association of stars that share a common origin and space velocity. Such runaway stars may be ejected by dynamic interactions between three or four stars. However, in this case the star may be a former component of a binary star system in which the more massive primary was destroyed in a Type II supernova explosion. The pulsar PSR B1929+10 may be the leftover remnant of this supernova, as it too was ejected from the association with a velocity vector that fits the scenario.
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Between 1966 and 1970, the Narrabri Stellar Intensity Interferometer was used to observe the pair and to directly measure the orbital characteristics and the angular diameter of the primary, which was found to be , and the angular size of the semi-major axis of the orbit was found to be only slightly larger at . Spica is a rotating ellipsoidal variable, which is a non-eclipsing close binary star system where the stars are mutually distorted through their gravitational interaction. This effect causes the apparent magnitude of the star system to vary by 0.03 over an interval that matches the orbital period. This slight dip in magnitude is barely noticeable visually.
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Zeta1 Muscae, Latinized from ζ1 Muscae and abbreviated ζ1 Mus, is a suspected astrometric binary star system in the constellation Musca, located 2.6° west of Beta Muscae. It is bright enough to be visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.73, forming a visual pair with nearby Zeta2 Muscae. The ζ1 Mus system is around 417 light-years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +21 km/s. The suspected astrometric component of the ζ1 Mus system was identified from acceleration behavior in the proper motion of the main star.
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Kepler-1647b (sometimes named Kepler-1647(AB)-b to distinguish it from the secondary component) is a circumbinary exoplanet that orbits the binary star system Kepler-1647, from Earth in the constellation Cygnus. It was announced on June 13, 2016 in San Diego at a meeting of the American Astronomical Society. It was detected using the transit method, when it caused the dimming of the primary star, and then again of the secondary star blended with the primary star eclipse. The first transit of the planet was identified in 2012, but at the time the single event was not enough to rule out contamination, or confirm it as a planet.
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A bow shock is being formed where the stellar wind is colliding with the surrounding interstellar medium. The peculiar velocity of Delta Cephei is relative to its neighbors. It is a suspected member of the Cep OB6 star cluster, and hence may be around the same age as the cluster: around 79 million years. At an angular separation of 40 arc seconds from Delta Cephei is a 7.5 magnitude companion star with the identifier HD 213307, called component C in multiple star catalogues, which is visible in small telescopes. HD 213307 itself is a binary star system with a combined stellar classification of B7-8 III-IV.
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5 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis, located about 770 light years away from the Sun as determined using parallax. With an apparent magnitude of 5.5, it can be seen with the naked eye as a faint, blue-white hued star. The system is moving further from the Earth with a heliocentric radial velocity of +2.4 km/s. The primary component is a B-type main sequence star with a stellar classification of B9.5 V. However, Abt and Morrell (1995) found a luminosity class of IV, suggesting it is instead a subgiant star that is evolving off the main sequence.
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Beta Scuti, Latinized from β Scuti, is a binary star system in the southern constellation Scutum. Based upon an annual parallax shift of 3.56 mas as seen from Earth, it is located approximately 920 light years from the Sun. The primary component has an apparent visual magnitude of +4.22 and is radiating about 1,270 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 4,622 K. This yellow-hued star is a G-type bright giant with a stellar classification of G4 IIa. This is a spectroscopic binary with an orbital period of 2.3 years and eccentricity around 0.35.
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It has expanded to 164 times the radius of the Sun and, on average, is radiating 4,390 times the Sun's luminosity from its swollen photosphere at an effective temperature of 3,674 K. The short-lived element technetium has been observed in the spectrum, an indicator of thermal pulses during helium shell burning. Based on the detection of excess ultraviolet excess, it is most likely a binary star system. An analysis of the motion of TW Horologii suggests a low-mass companion, although the UV excess suggests it is hot. In 2013 the luminosity of Mira variables, based on Hipparcos parallaxes, was used to calibrate a Period-luminosity relationship for carbon stars.
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On August 7, 2010, the Infrared Array Camera aboard the Spitzer Space Telescope was used to find the centroid, the point in space around which both of the Kepler-14 stars orbit. Analysis of the collected data determined which component of the binary star system was the site of the transit signal, and, additionally, that the transit signal came from the primary star in the system (as opposed to the fainter, less prominent star). Using the spectral data collected by HIRES and FIES, the Kepler team derived the characteristics of the host star. The HIRES and FIES results agreed on every aspect of the star that had been derived except for the star's radial velocity.
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4 Sagittarii is a suspected astrometric binary star system in the zodiac constellation of Sagittarius, located approximately 390 light years away based on parallax. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.74, The system is moving closer to the Earth with a heliocentric radial velocity of −18 km/s. The visible component is a B-type main-sequence star with a stellar classification of B9 V. It has a high rate of spin, displaying a projected rotational velocity of 149 km/s. This is giving it an oblate shape with an equatorial bulge that is an estimated 14% larger than the polar radius.
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Discovered in 1977, it is a relatively unobscured galaxy (magnitude 10.6), which is unusual for galaxies located in constellations near the Milky Way, since their dim light is obscured by gas and dust. This oblong spiral galaxy with 6.9 by 3.0 arcminutes and 26,000 light-years in diameter, is located 13 million light-years away from Earth and lies 4 degrees off the galactic plane. It is the closest Seyfert galaxy to the Milky Way, and therefore hosts an active galactic nucleus. The Chandra X-ray Observatory's false-color image of Circinus X-1 showing its jets Circinus X-1 is an X-ray binary star system that includes a neutron star.
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In some systems, several of these wormholes are found to be co-located forming an irresistible trading nexus, perhaps because their ends have some mathematical affinity: they occur with entrances relatively close together in very small spatial volumes. The greatest known aggregation of these co-located "Junctions" or Terminus Loci occurs in the Manticore binary star system, whose wormholes connect the wormhole junction to six (later seven) other star systems, giving the Manticore system an astrographic position to be coveted, and an immense revenue stream from transit tolls, manufacturing and trade, and a large carrying trade. In the stories, no means of faster-than-light interstellar communications exists. Messages between star systems must be physically carried by starships.
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To help explain why this star is so small, it is hypothesized it was once part of a binary star system. HE0107-5240 was found by Norbert Christlieb and colleagues at the University of Hamburg in Germany as a byproduct of the Hamburg/ESO Survey for faint quasars with the 1m ESO Schmidt telescope. Follow-up observations were made at the Siding Spring 2.3 m Telescope and high-resolution spectra were taken at the European Southern Observatory in Chile, using one of the units of the Very Large Telescope. In 2005, a second star with an even smaller iron abundance, HE 1327-2326 ([Fe/H]=-5.4), was found, also in the Hamburg/ESO survey.
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Eta Piscis Austrini (η Piscis Austrini) is binary star system in the southern constellation of Piscis Austrinus. As of 2000, the two components had an angular separation of 1.818 arc seconds along a position angle of 113.4°. The pair have a combined apparent visual magnitude of +5.43, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 3.99 mas as seen from the Earth, the system is located roughly 820 light years from the Sun. The magnitude 5.7 primary, component A, is a blue-white hued Be star with a stellar classification B8 V. At the age of 115, the star is spinning rapidly with a projected rotational velocity of 265.
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Epsilon Pyxidis has been catalogued as an Am star, although this remains uncertain. It has double the mass of the Sun and radiates 19 times the Sun's luminosity from its photosphere at an effective temperature of 6,368 K. In addition to a close companion of unknown type at an angular separation of 0.17 arc seconds, the primary shares an orbit with a binary star system, components B and C, that lie at an angular separation of 17.8 arc seconds. At the estimated distance of this system, this corresponds to a projected separation of around 1,150 AU. The B/C pair consist of visual magnitude 10.5 and 10.8 stars with a mean separation of 0.3 arc seconds.
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It is moving closer to the Earth with a heliocentric radial velocity of −50 km/s, and is predicted to come as near as in around 3.3 million years. This is an aging giant star with a stellar classification of K5 III, having exhausted the supply of hydrogen at its core and expanded to 42 times the Sun's radius. It is radiating 391 times the luminosity of the Sun from its photosphere at an effective temperature of 3,972 K. 56 Aquilae is a double star, but it does not appear to be a binary star system. It is one of the double stars profiled in Admiral William Henry Smyth's 1864 work, Sidereal Chromatics.
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Pi Centauri, Latinized from π Centauri, is a binary star system in the southern constellation of Centaurus. It has a blue-white hue and is visible to the naked eye with a combined apparent visual magnitude of +3.90. The system is located at a distance of approximately 360 light years from the Sun based on parallax, and is drifting further away with a radial velocity of around +9 km/s. It is a member of the Lower Centaurus-Crux subgroup of the Scorpius–Centaurus Association. The magnitude +4.08 primary, designated component A, is a B-type main-sequence star with a stellar classification of B5Vn, where the 'n' suffix indicates broad, diffuse (nebulous) lines due to rapid rotation.
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This stellar pair form a binary star system separated by about 74 arc seconds (~434 AU). This system is also known for its high proper motion of about 1 arc second a year. In August 2018, a group of scientist using measurements taken from the CARMENES spectrograph, on the Calar Alto Observatory located in Spain, announced they had detected a planet orbiting the larger of the stars, HD 180617 (Gliese 752 A). The measurements indicated the presence of a planet with a minimum mass comparable to Neptune on an orbit partly located within the habitable zone. The name and number are from the Catalogue of Nearby Stars, published by German astronomer Wilhelm Gliese in 1969.
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The mass is equally uncertain, thought to have been over 100 times the Sun when initially formed but now considerably less due to extreme mass loss. Modelling the star itself to match its spectrum gives a mass of , while matching its current properties to an evolutionary model gives a much higher mass (). Earlier studies once claimed the Pistol Star as the most massive star known at around . Later studies have reduced its estimated luminosity making it a candidate luminous blue variable about (one-third as luminous as the binary star system Eta Carinae), hence a radius of based on an effective temperature around , or as high as , hence a correspondingly radius of .
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Four hundred years later, a group of German armed militia known as the Stormtroopers raid the monastery, executing all but one of the Jesuit monks living there, recovering the Santiago manuscript. Meanwhile, another party raids DARPA (The Defence Advanced Research Projects Agency) headquarters in order to capture a new superweapon known as the Supernova. DARPA sends Colonel Frank Nash to Peru with the aid of NYU linguistics professor William Race to recover the idol before anyone else can retrieve it. Their mission: to retrieve 'the Spirit of the People' (as the natives call it), carved out of Thyrium-261, a nuclear material from a binary star system that came to Earth via a meteorite.
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It has an 11.3 magnitude common proper motion companion at an angular separation of 5.9 arcseconds, which may make this a binary star system if the pair are gravitationally bound. This is an F-type main sequence star with a stellar classification of F2 V, where the luminosity class V indicates that it is generating energy through the nuclear fusion of hydrogen at its core. It is slightly larger than the Sun, with 108% of the Sun's mass and 139% of the Sun's radius. HD 49933 emits 3.47 times as much energy as the Sun from its outer atmosphere at a higher effective temperature of about 6,598 K, giving it the yellow-white hue of an F-type star.
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It is a main-sequence star of spectral class K2, which means that energy generated at the core through nuclear fusion of hydrogen is emitted from the surface at a temperature of about , giving it an orange hue. The Bayer designation ε Eridani (Latinised as Epsilon Eridani) was established in 1603 by Johann Bayer. It may be a member of the Ursa Major Moving Group of stars that share a similar motion through the Milky Way, implying these stars shared a common origin in an open cluster. Its nearest neighbour, the binary star system Luyten 726-8, will have a close encounter with Epsilon Eridani in approximately 31,500 years when they will be separated by about .
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This star was shown to be itself a close double star by S. W. Burnham in 1888, and he discovered an additional 14th-magnitude companion at an angular separation of 31″. Follow on measurements of proper motion showed that Herschel's companion was diverging from Aldebaran, and hence they were not physically connected. However, the companion discovered by Burnham had almost exactly the same proper motion as Aldebaran, suggesting that the two formed a wide binary star system. Working at his private observatory in Tulse Hill, England, in 1864 William Huggins performed the first studies of the spectrum of Aldebaran, where he was able to identify the lines of nine elements, including iron, sodium, calcium, and magnesium.
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This is an evolved, yellow-hued giant of spectral type K0 III around 2.16 times as massive as the Sun that has swollen to a diameter 10 times that of the Sun. It is a red clump star on the horizontal branch, which indicates it is generating energy through helium fusion at its core. The star is radiating 51 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,699 K. Gamma2 Normae is a close double, with a magnitude 10 companion. The pair has been previously identified as a binary star system, but the second release of Gaia data showed the companion star to be much more distant.
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It is a member of the Upper Centaurus Lupus subgroup of the nearby Scorpius–Centaurus Association. This is a visual binary star system with the components having an angular separation of 0.1 arc seconds. The primary, component A, is a magnitude 4.84 B-type subgiant star with a stellar classification of B5 V. It displays radial velocity variations indicating it has an unseen second companion orbiting at a separation of at least 17 AU with a period of 27 years or more. The spectrum of the primary displays a Zeeman effect indicating a magnetic field with a strength ranging from −94 to 677 G. The visible companion, component B, has a visual magnitude of 5.27.
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99 Herculis is the Flamsteed designation for a binary star system in the northern constellation of Hercules. It has the Bayer designation b Herculis, while 99 Herculis is the Flamsteed designation. This system has an apparent visual magnitude of 5.1, which, according to the Bortle scale, makes it faintly visible to the naked eye from suburban skies. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.064″, corresponding to a physical distance of about from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of +1.7 km/s. The binary nature of this star system was first discovered in 1859 by English astronomer W. R. Dawes.
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A planetary system has been inferred to exist around NN Ser by several teams. All of these teams rely on the fact that Earth sits in the same plane as the NN Serpentis binary star system, so humans can see the larger red dwarf eclipse the white dwarf every 0.13 days. Astronomers are then able to use these frequent eclipses to spot a pattern of small but significant irregularities in the orbit of stars, which could be attributed to the presence and gravitational influence of circumbinary planets. Chen (2009) used these "eclipse timing variations" to suggesting a putative orbital period spanning between 30 and 285 years and a minimum mass between 0.0043 and 0.18 Solar masses.
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HD 119124 is a wide binary star system in the circumpolar constellation of Ursa Major. With an apparent visual magnitude of 6.3, it lies below the normal brightness limit of stars that are visible with the naked eye under most viewing conditions. An annual parallax shift of 39.24 mas for the A component provides a distance estimate of 83 light years. The pair are candidate members of the Castor Moving Group, which implies a relatively youthful age of around 200 million years. HD 119124 is moving closer to the Sun with a radial velocity of −12 km/s. This system was first identified as a double star by Friedrich von Struve (1793−1864) and catalogued as the 1774th entry in his list.
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The constellation Canis Minor as it can be seen by the naked eye. Canis Minor contains only two stars brighter than fourth magnitude. At magnitude 0.34, Procyon, or Alpha Canis Minoris, is the seventh-brightest star in the night sky, as well as one of the closest. Its name means "before the dog" or "preceding the dog" in Greek, as it rises an hour before the "Dog Star", Sirius, of Canis Major. It is a binary star system, consisting of a yellow-white main sequence star of spectral type F5 IV-V, named Procyon A, and a faint white dwarf companion of spectral type DA, named Procyon B. Procyon B, which orbits the more massive star every 41 years, is of magnitude 10.7.
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The masses of the two pre-merger black holes provide information about stellar evolution. Both black holes were more massive than previously discovered stellar-mass black holes, which were inferred from X-ray binary observations. This implies that the stellar winds from their progenitor stars must have been relatively weak, and therefore that the metallicity (mass fraction of chemical elements heavier than hydrogen and helium) must have been less than about half the solar value. The fact that the pre-merger black holes were present in a binary star system, as well as the fact that the system was compact enough to merge within the age of the universe, constrains either binary star evolution or dynamical formation scenarios, depending on how the black hole binary was formed.
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A significant number of black holes must receive low natal kicks (the velocity a black hole gains at its formation in a core-collapse supernova event), otherwise the black hole forming in a binary star system would be ejected and an event like GW would be prevented. The survival of such binaries, through common envelope phases of high rotation in massive progenitor stars, may be necessary for their survival. The majority of the latest black hole model predictions comply with these added constraints. The discovery of the GW merger event increases the lower limit on the rate of such events, and rules out certain theoretical models that predicted very low rates of less than 1 Gpc−3yr−1 (one event per cubic gigaparsec per year).
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The scenario created was that of a binary star system in the Messier 13 globular cluster with an Earthlike planet called Troas (or more informally, Junior) located at one of the system's Lagrangian points. An earlier expedition to Troas had suffered some mysterious disaster, and a second expedition was being mounted to determine if the planet was suitable for colonization, and to find out what happened to the first expedition. Anderson finished his story, and Asimov finished a story called "Sucker Bait", but Blish (or Kidd) never completed the third story, and the proposed book never saw print. Anderson was able to sell Question and Answer to Astounding (where it appeared a few months after "Sucker Bait") and later to Ace Books.
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Wojciech Krzemiński was one of the first observers, who in the 1960s demonstrated the dual nature of cataclysmic variables. Together with Joseph Taste suggested that these objects are in process of accretion of matter and correctly interpret their light curve change as coming from the accretion disk impacted through a narrow stream of matter flowing through the inner Lagrange point of less massive component of binary star system. Also in the 1960s, he performed accurate measurements of the brightness of dwarf novae like U Geminorum, discovered on 4 December 1961. The marked eclipse of U Geminorum repeated with a period of 4 hours 14 minutes and 45 seconds for the first time clearly demonstrating that we are dealing with a double system.
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This is a wide binary star system with a projected separation of 100 astronomical units; indicating that the two stars are at least this distance apart. The primary component is a solar-type main sequence star with a stellar classification of G1 V. It has about 99% of the Sun's mass, 111% of the Sun's radius, and shines with 139% of the luminosity of the Sun. This energy is being emitted from an outer envelope at an effective temperature of 5,922 K, giving it the golden hue of a G-type star. An examination of the primary component with the Spitzer space telescope failed to detect any infrared excess that might otherwise be an indication of a circumstellar debris disk.
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Lazar additionally claimed that during his joining the program, he read briefing documents describing the historical involvement of Earth for the past 10,000 years with extraterrestrial beings described as grey aliens from a planet orbiting the twin binary star system Zeta Reticuli. As of September 2019, no extrasolar planets have been found in the Zeta Reticuli system. In 1989, Lazar said the seats of the saucer he saw were approximately child-sized and that he had seen alien cadavers of a corresponding size.. Event occurs at 54. He also said that while walking down a hallway at S-4, he briefly glanced through a door window and saw what he interpreted as two men in lab coats facing down and talking to "something small with long arms".
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An X-ray pulsar consists of a magnetized neutron star in orbit with a normal stellar companion and is a type of binary star system. The magnetic-field strength at the surface of the neutron star is typically about 108 Tesla, over a trillion times stronger than the strength of the magnetic field measured at the surface of the Earth (60 μT). Gas is accreted from the stellar companion and is channeled by the neutron star's magnetic field on to the magnetic poles producing two or more localized X-ray hot spots, similar to the two auroral zones on Earth, but far hotter. At these hotspots the infalling gas can reach half the speed of light before it impacts the neutron star surface.
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It is separated by 2.1 arcseconds from a magnitude 10 star. Theta Pyxidis is a red giant of spectral type M1III and semi-regular variable with two measured periods of 13 and 98.3 days, and an average magnitude of 4.71, and is 500 ± 30 light-years distant from Earth. It has expanded to approximately 54 times the diameter of the Sun. alt=An image of a central white object surrounded by white and pale blue markers signifying material in a shell-like pattern around it Located around 4 degrees northeast of Alpha is T Pyxidis, a binary star system composed of a white dwarf with around 0.8 times the Sun's mass and a red dwarf that orbit each other every 1.8 hours.
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A binary star system can also produce eclipses if the plane of the orbit of its constituent stars intersects the observer's position. For the special cases of solar and lunar eclipses, these only happen during an "eclipse season", the two times of each year when the plane of the Earth's orbit around the Sun crosses with the plane of the Moon's orbit around the Earth. The type of solar eclipse that happens during each season (whether total, annular, hybrid, or partial) depends on apparent sizes of the Sun and Moon. If the orbit of the Earth around the Sun, and the Moon's orbit around the Earth were both in the same plane with each other, then eclipses would happen each and every month.
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Artist's impression of the binary star system AR Scorpii The components of binary stars are denoted by the suffixes A and B appended to the system's designation, A denoting the primary and B the secondary. The suffix AB may be used to denote the pair (for example, the binary star α Centauri AB consists of the stars α Centauri A and α Centauri B.) Additional letters, such as C, D, etc., may be used for systems with more than two stars. In cases where the binary star has a Bayer designation and is widely separated, it is possible that the members of the pair will be designated with superscripts; an example is Zeta Reticuli, whose components are ζ1 Reticuli and ζ2 Reticuli.
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The merger process of two co-orbiting white dwarfs produces gravitational waves If a white dwarf is in a binary star system and is accreting matter from its companion, a variety of phenomena may occur, including novae and Type Ia supernovae. It may also be a super-soft x-ray source if it is able to take material from its companion fast enough to sustain fusion on its surface. On the other hand, phenomena in binary systems as tidal interaction and star-disc interaction, moderated by magnetic fields or not, act on the rotation of accreting white dwarfs. In fact, the fastest-spinning, securely known white dwarfs, are members of binary systems (being the white dwarf in CTCV J2056-3014 the fastest one).
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The metallicity of this star – what astronomers term the abundance of elements with atomic numbers greater than helium – is near solar. The star has 79% of the mass of the Sun and 73% of the Sun's radius. It is radiating 22.5% of the luminosity of the Sun from its photosphere at an effective temperature of 4,712 K. A magnitude 10.16 common proper motion companion, designated component B, is located at an angular separation of along a position angle of 181° from the primary, as of 2015. This is a suspected binary star system with components of individual visual magnitude 10.6 and 11.1, and a class of M2.5 V. The coordinates of this companion are a source of X-ray emission.
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61 Cygni is a binary star system in the constellation Cygnus, consisting of a pair of K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitude 5.20 and 6.05, respectively, they can be seen with binoculars in city skies or with the naked eye in rural areas without photopollution. 61 Cygni first attracted the attention of astronomers when its large proper motion was first demonstrated by Giuseppe Piazzi in 1804. In 1838, Friedrich Bessel measured its distance from Earth at about 10.4 light- years, very close to the actual value of about 11.4 light-years; this was the first distance estimate for any star other than the Sun, and first star to have its stellar parallax measured.
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In 1904, he published in Astronomische Nachrichten an article titled Untersuchungen über den Lichtwechsel von ε Aurigae (Investigations of the Light Changes of Epsilon Aurigae), where he suggested the star was an Algol variable and an eclipsing binary. The first hypothesis, set forth in 1937 by astronomers Gerard Kuiper, Otto Struve, and Bengt Strömgren, suggested that Epsilon Aurigae was a binary star system containing an F2 supergiant and an extremely cool "semitransparent" star that would completely eclipse its companion. However, the eclipsing star would scatter light emitted by its eclipsed companion resulting in the observed decrease in magnitude. The scattered light would be detected on Earth as a star visible to the naked eye, although this light would be significantly dimmed.
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K2-288Bb (previously designated EPIC 210693462 b) is a super-Earth or mini- Neptune exoplanet orbiting in the habitable zone of K2-288B, a low-mass M-dwarf star in a binary star system in the constellation of Taurus about 226 light-years from Earth. It was discovered by citizen scientists while analysing data from the Kepler spacecraft's K2 mission, and was announced on 7 January 2019. K2-288 is the third transiting planet system identified by the Exoplanet Explorers program, after the six planets of K2-138 and the three planets of K2-233. K2-288Bb is likely to be in the habitable zone of its host star, and thus may be capable on supporting life, though the planet's composition is unknown.
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The mass of the molecular gas in the nebula is estimated to be in the range of 0.34–, and is much greater than the mass of the ionized gas. The central binary star system, which has an orbital period of days, is also variable, probably due to dust in orbit around it. The dust itself is heated by the central star and so NGC 2346 is unusually bright in the infrared part of the spectrum. When one of the two stars evolved into a red giant, it engulfed its companion, which stripped away a ring of material from the larger star's atmosphere. When the red giant's core was exposed, a fast stellar wind inflated two ‘bubbles’ from either side of the ring.
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FN Canis Majoris is a binary star system in the southern constellation Canis Major, near the northern constellation border with Monoceros. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.41. The system is located at a distance of approximately 3,000 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +31 km/s. It is a runaway star associated with the Sh 2-296 nebula in the CMa OB1 association, and has a conspicuous bow-shock feature. The brighter component is a visual magnitude 5.69 B-type star that has been assigned various stellar classification from B0 III/IV to B2 Ia/ab, suggesting it is an evolved state.
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Avoiding Bolt, the law, and an incited mob convinced the children are witches, they eventually make their way up Witch Mountain, pursued by Deranian and Ubermann, as well as by Bolt in a helicopter. As their memories begin to fully return, the children realize their accident at sea did not involve a boat but a spacecraft. Tony and Tia are actually of extraterrestrial origin; the double star emblem on the star case stands for a binary star system where their home planet was located. Having come to Earth because their own planet was dying, survivors of the journey made their way to Witch Mountain and formed a community to await the surviving children, each pair in possession of a star case to help them find their way to their new home.
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SX Corvi is an eclipsing binary star system in the constellation Corvus, ranging from apparent magnitude 8.99 to 9.25 over 7.5 hours. The system is a contact binary also known as a W Ursae Majoris variable, where the two component stars orbit closely enough to each other for mass to have been transferred between them—in this case the secondary having transferred a large amount of mass to the primary. Yildiz and colleagues estimated the age of the system at 7.32 ± 0.97 billion years based on study of the properties of the system and estimated rate of mass transfer. They found the current masses of the primary and secondary to be 1.25 ± 0.04 and 0.10 ± 0.01 solar masses respectively, from their original masses of 0.72 ± 0.02 and 1.68 ± 0.05 solar masses.
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Gliese 15 Ac (also known as Groombridge 34 Ac) is an exoplanet orbiting the nearby red dwarf star Gliese 15 A (Groombridge 34 A), which is part of a binary star system located about 11.6 light-years from the Sun. The planet was first proposed in October 2017 using radial velocity data from the CARMENES spectrograph, combined with measurements from the HARPS and HIRES spectrographs, and its existence was confirmed in April 2018 using HARPS-N data. It has a minimum mass 36 times that of Earth and orbits at around 5.4 astronomical units with a period of , an orbit which may have been sculpted by interaction with the companion star, Gliese 15 B. As of 2020, Gliese 15 Ac is the longest-period sub-Jovian planet discovered by radial velocity.
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Procyon is the brightest star in the constellation of Canis Minor and usually the eighth-brightest star in the night sky, with a visual apparent magnitude of 0.34. It has the Bayer designation α Canis Minoris, which is Latinised to Alpha Canis Minoris, and abbreviated α CMi or Alpha CMi, respectively. As determined by the European Space Agency Hipparcos astrometry satellite, this system lies at a distance of just , and is therefore one of Earth's nearest stellar neighbours. A binary star system, Procyon consists of a white-hued main-sequence star of spectral type F5 IV–V, designated component A, in orbit with a faint white dwarf companion of spectral type DQZ, named Procyon B. The pair orbit each other with a period of 40.8 years and an eccentricity of 0.4.
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The neutron star RX J0822-4300, which was measured to move at a record speed of over 1,500 km/s (0.5% of the speed of light) in 2007 by the Chandra X-ray Observatory, is thought to have been produced the first way. One theory regarding the ignition of Type Ia supernovae invokes the onset of a merger between two white dwarfs in a binary star system, triggering the explosion of the more massive white dwarf. If the less massive white dwarf is not destroyed during the explosion, it will no longer be gravitationally bound to its destroyed companion, causing it to leave the system as a hypervelocity star with its pre-explosion orbital velocity of 1000–2500 km/s. In 2018, three such stars were discovered using data from the Gaia satellite.
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HR 4523 (66 G. Centauri) is a binary star system that is located in the northeastern part of the Centaurus constellation, at a distance of about from the Solar System. The larger member of the system is a G-type star that is smaller than the Sun but of similar mass. It has a common proper motion companion that was discovered by W. J. Luyten in 1960. This M-type star appears to be in a wide orbit around the primary at a current separation of about 211 astronomical units (AU), (or 211 times the separation of the Earth from the Sun). By comparison, Neptune orbits at an average distance of 30 AU. The stellar classification for the primary star in this system is G2V; the same as the Sun.
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The Fibre-Fed Echelle Spectrograph, or FIES, was the instrument that collected these observations between December 2008 and April 2009; also used was the CORALIE spectrograph on the Leonhard Euler Telescope at Chile's La Silla Observatory, which collected additional radial velocity and spectral measurements. Analysis of WASP-24's spectrum ruled out the possibility that WASP-24 is a rapidly rotating star, which could make confirmation of a planet difficult, or that it is a spectroscopic binary star system. Use of a span bisector analysis revealed that the star is not very active. WASP-24 was then observed using Hawaii's Faulkes Telescope North and Australia's Faulkes Telescope South, searching for a period at which the discovered planet WASP-24b might transit, or cross in front of, its star, over various days in 2009 and 2010.
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Gamma Cephei (γ Cephei, abbreviated Gamma Cep, γ Cep) is a binary star system approximately 45 light-years away in the constellation of Cepheus. The primary (designated Gamma Cephei A, officially named Errai , the traditional name of the system) is a stellar class K1 orange giant or subgiant star; it has a red dwarf companion (Gamma Cephei B). An exoplanet (designated Gamma Cephei Ab, later named Tadmor) has been confirmed to be orbiting the primary. Gamma Cephei is the naked-eye star that will succeed Polaris as the Earth's northern pole star, due to the precession of the equinoxes. It will be closer to the northern celestial pole than Polaris around 3000 CE and will make its closest approach around 4000 CE. The 'title' will pass to Iota Cephei some time around 5200 CE.
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Many notable objects are too faint to be seen with the naked eye. AX Microscopii, better known as Lacaille 8760, is a red dwarf which lies only 12.9 light-years from the Solar System. At magnitude 6.68, it is the brightest red dwarf in the sky. BO Microscopii is a rapidly rotating star that has 80% the diameter of the Sun. Nicknamed "Speedy Mic", it has a rotation period of 9 hours 7 minutes. An active star, it has prominent stellar flares that average 100 times stronger than those of the Sun, and are emitting energy mainly in the X-ray and ultraviolet bands of the spectrum. It lies 218 ± 4 light-years away from the Sun. AT Microscopii is a binary star system, both members of which are flare star red dwarfs.
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Sigma Tauri (σ Tauri) is the Bayer designation for a pair of white-hued stars in the zodiac constellation of Taurus. The system is a visual double star, whose components are designated σ1 Tauri and σ2 Tauri, with the latter being the more northerly star. The two are separated by 7.2 arcminutes on the sky and can be readily split with a pair of binoculars. They have apparent visual magnitudes of +5.07 and +4.70, respectively, which indicated they are both visible to the naked eye. Based upon parallax measurements, σ1 Tauri is about 147 light years from the Sun, while σ2 Tauri is 156 light years distant. σ1 Tauri is a single-lined spectroscopic binary star system with an orbital period of 38.951 days and an eccentricity of 0.15.
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V1191 Cygni is the variable star designation for an overcontact binary star system in the constellation Cygnus. First found to be variable in 1965, it is a W Ursae Majoris variable with a maximum apparent magnitude 10.82. It drops by 0.33 magnitudes during primary eclipses with a period of 0.3134 days, while dropping by 0.29 magnitudes during secondary eclipses. The primary star, which is also the cooler star, appears to have a spectral type of F6V, while the secondary is slightly cooler with a spectral type of G5V. With a mass of 1.29 solar masses and a luminosity of 2.71 solar luminosities, it is slightly more massive and luminous than the sun, while the secondary is only around 1/10 as massive and less than half as luminous.
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The source in the LMC appeared extended and contained star ε Dor. The X-ray luminosity (Lx) over the range 1.5–12 keV was 6 × 1031 W (6 × 1038 erg/s). DEM L316A is located some 160,000 light-years away in the Large Magellanic Cloud The Large Magellanic Cloud (LMC) appears in the constellations Mensa and Dorado. LMC X-1 (the first X-ray source in the LMC) is at RA Dec , and is a high-mass X-ray binary (star system) source (HMXB). Of the first five luminous LMC X-ray binaries: LMC X-1, X-2, X-3, X-4 and A 0538–66 (detected by Ariel 5 at A 0538–66), LMC X-2 is the one that is a bright low-mass X-ray binary system (LMXB) in the LMC.
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WASP-15 was first observed by the WASP-South branch of the SuperWASP project, which operates from the South African Astronomical Observatory, between May 4, 2006 and July 17, 2006. It was later observed by WASP-South from January 31, 2007 to July 17, 2007 and from January 31, 2008 to May 29, 2008. Further analysis taken from 24,943 collected data points revealed eleven full or partial transits. Follow-up observations were conducted by a European and American science team at the 1.2 m Leonhard Euler Telescope at La Silla Observatory in Chile, which further raised the possibility of the existence of a planet in WASP-15's orbit; use of the CORALIE spectrograph on the Euler Telescope between March 6, 2008 and July 17, 2008 revealed that the variations in radial velocity measurements were not because of an eclipsing binary star system.
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If a planet orbits one member of a binary star system, then an uppercase letter for the star will be followed by a lowercase letter for the planet. Examples are 16 Cygni Bb and HD 178911 Bb. Planets orbiting the primary or "A" star should have 'Ab' after the name of the system, as in HD 41004 Ab. However, the "A" is sometimes omitted; for example the first planet discovered around the primary star of the Tau Boötis binary system is usually called simply Tau Boötis b. The star designation is necessary when more than one star in the system has its own planetary system such as in case of WASP-94 A and WASP-94 B. If the parent star is a single star, then it may still be regarded as having an "A" designation, though the "A" is not normally written.
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Stellar multiplicity increases with stellar mass: the likelihood of stars being in multiple systems is about 25% for red dwarfs, about 45% for Sun-like stars, and rises to about 80% for the most massive stars. Of the multiple stars about 75% are binaries and the rest are higher-order multiplicities.Stellar Multiplicity, Gaspard Duchêne (1,2), Adam Kraus (3) ((1) UC Berkeley, (2) Institut de Planétologie et d'Astrophysique de Grenoble, (3) Harvard- Smithsonian CfA), (Submitted on 12 Mar 2013) More than one hundred planets have been discovered orbiting one member of a binary star system (e.g. 55 Cancri, possibly Alpha Centauri Bb),BINARY CATALOGUE OF EXOPLANETS , Maintained by Richard Schwarz], retrieved 28 Sept 2013 and several circumbinary planets have been discovered which orbit around both members of a binary star (e.g. PSR B1620-26 b, Kepler-16b).
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Schematic of a binary star system with one planet on an S-type orbit and one on a P-type orbit While a number of binary star systems have been found to harbor extrasolar planets, such systems are comparatively rare compared to single star systems. Observations by the Kepler space telescope have shown that most single stars of the same type as the Sun have plenty of planets, but only one-third of binary stars do. According to theoretical simulations, even widely separated binary stars often disrupt the discs of rocky grains from which protoplanets form. On the other hand, other simulations suggest that the presence of a binary companion can actually improve the rate of planet formation within stable orbital zones by "stirring up" the protoplanetary disk, increasing the accretion rate of the protoplanets within.
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HR 5553 is a binary star system located thirty-eight light-years away from the Sun, in the northern constellation Boötes. It has the variable star designation DE Boötis, and is classified as an RS Canum Venaticorum variable that ranges in apparent visual magnitude from 5.97 down to 6.04, which is bright enough to be dimly visible to the naked eye. The system is drifting closer to the Sun with a radial velocity of −30 km/s, and is expected to come as close as in 210,000 years. Orbital elements for this single-lined spectroscopic binary was first calculated in 1981 using radial velocity measurements from David Dunlap Observatory combined with older measurements from Mount Wilson Observatory and Dominion Astrophysical Observatory. The two stars orbit each other with a period of 125 days and a large eccentricity of 0.51.
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Beta Piscis Austrini (β Piscis Austrini) is catalogued as a binary star system in the southern constellation of Piscis Austrinus. It is visible to the naked eye with an apparent visual magnitude of +4.29. Based upon an annual parallax shift of 22.84 mas as seen from the Earth, the star is located 143 light years from the Sun. These coordinates are a source of X-ray emission with a luminosity of , which is most likely coming from a source other than the A-type stars. Oblak (1978) identified this as a triple star system, although subsequent sources list it as a binary. The magnitude 4.29 primary, component A, is a white-hued A-type main sequence star with a stellar classification of A1 V. It has an estimated 2.3 times the mass of the Sun and 2.1 times the Sun's radius.
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Two supernovae have been detected in Centaurus A. The first supernova, named SN 1986G, was discovered within the dark dust lane of the galaxy by R. Evans in 1986. It was later identified as a Type Ia supernova, which forms when a white dwarf's mass grows large enough to ignite carbon fusion in its center, touching off a runaway thermonuclear reaction, as may happen when a white dwarf in a binary star system strips gas away from the other star. SN 1986G was used to demonstrate that the spectra of type Ia supernovae are not all identical, and that type Ia supernovae may differ in the way that they change in brightness over time. The second supernova, dubbed SN2016adj, was discovered by Backyard Observatory Supernova Search in February 2016 and was initially classified as a Type II supernova based on its H-alpha emission line.
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Extraterrestrial (also Alien Worlds in the UK) is a British-American two-part television documentary miniseries, aired in 2005 in the UK by Channel 4, by the National Geographic Channel (as Extraterrestrial) in the US on Monday, May 30, 2005 and produced by Big Wave Productions Ltd. The program focuses on the hypothetical and scientifically feasible evolution of alien life on extrasolar planets, providing model examples of two different fictional worlds, one in each of the series's two episodes. The documentary is based on speculative collaboration of a group of American and British scientists, who were collectively commissioned by National Geographic. For the purposes of the documentary, the team of scientists divides two hypothetical examples of realistic worlds on which extraterrestrial life could evolve: A tidally locked planet (dubbed "Aurelia") orbiting a red dwarf star and a large moon (dubbed "Blue Moon") orbiting a gas giant in a binary star system.
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The primary star, ε Sagittarii A, of this binary star system has a stellar classification of B9.5 III, with the luminosity class of III suggesting this is an evolved giant star that has exhausted the supply of hydrogen at its core. The interferometry-measured angular diameter of this star, after correcting for limb darkening, is , which, at its estimated distance, equates to a physical radius of about 6.8 times the radius of the Sun. This is a close match to the empirically-determined value of 6.9 solar radii. It has about 3.5 times the mass of the Sun and is radiating around 363 times the Sun's luminosity from its outer atmosphere at an effective temperature of 9,960 K. At this heat, the star glows with a blue-white hue. This star is spinning rapidly with a projected rotational velocity of 236 km s−1.
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The spectrum of this star matches a stellar classification of G8 II-III, with the luminosity class notation 'II-III' indicating it shows some traits of both a giant star and a bright giant. At this evolutionary stage, the atmosphere has expanded to almost thirteen times the radius of the Sun and the outer envelope has an effective temperature of 5,196 K. X-ray emission has been detected from this star, with an estimated luminosity of . Alpha Reticuli has a 12th-magnitude visual companion, CCDM J04144-6228B, at an angular separation of 48 arcseconds away along a position angle of 355°. Since the two stars share a common proper motion across the celestial sphere, it is possible that Alpha Reticuli, rather than being solitary, may instead be the primary component of a binary star system with an orbital period of, at least, 60,000 years.
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The story's protagonist is Poilar Crookleg, member of a humanoid race with a pastoral civilization at a level roughly corresponding to that of the Iron Age of human civilization. Only as the story develops it becomes apparent that these people are not humans; their hands have an additional opposing thumb, and they have limited shapeshifting abilities which allows them to loosen their joints, to adapt their skin and inner organs to environmental changes, and to extrude suction cups for climbing. Shapeshifting is also an intrinsic part of their sexuality, for in the absence of sexual arousal both sexes maintain a neuter form without overt gender characteristics. The planet is located in a binary star system where it seems to be in orbit around the major white and luminous component, Ekmelios (probably an F-type star) while reddish Marilemma (apparently an M-type red dwarf) is much more distant.
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Kappa Geminorum (κ Geminorum, κ Gem) is a binary star system in the northern zodiac constellation of Gemini. It is visible to the naked eye with an apparent visual magnitude of 3.568. Based upon an annual parallax shift of 23.07 mas, the system is located about 141 light years distant from the Sun. In Chinese astronomy, Kappa Geminorum is called 積薪, Pinyin: Jīxīn, meaning Pile of Firewood, because this star is marking itself and stand alone in Pile of Firewood asterism, Well mansion (see : Chinese constellation). AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 16 日 積薪 (Jīxīn) westernized into Tseih Tsing, but the name Tseih Tsing was designated for χ Gem and μ Cnc by R.H. Allen, with the meaning is "piled-up fuel" In Japanese, 隆博星 (Takahiro-boshi), meaning "Esteemed Nobility Star," refers to the Japanese description of κ Geminorum.
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32 Pegasi is a binary star system in the northern constellation of Pegasus. It is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude of 4.81 The system is located approximately 560 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +11.4 km/s. The brighter member of this system, designated component Aa, has visual magnitude 4.83 with a stellar classification of B9III, matching a late B-type star with the luminosity class of a giant. It is spinning with a projected rotational velocity of 60 km/s, and is radiating 541 times the luminosity of the Sun from its photosphere at an effective temperature of 11,403 K. The fainter secondary, component Ab, is of magnitude 8.86 with an angular separation of along a position angle of 288° from the primary, as of 2005.
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Nonetheless, some physicists continued to doubt whether radiation would be produced by a binary star system, where the world lines of the centers of mass of the two stars should, according to the EIH approximation (dating from 1938 and due to Einstein, Infeld, and Banesh Hoffmann), follow timelike geodesics. Inspired by conversations by Felix Pirani, Hermann Bondi took up the study of gravitational radiation, in particular the question of quantifying the energy and momentum carried off 'to infinity' by a radiating system. During the next few years, Bondi developed the Bondi radiating chart and the notion of Bondi energy to rigorously study this question in maximal generality. In 1957, at a conference at Chapel Hill, North Carolina, appealing to various mathematical tools developed by John Lighton Synge, A. Z. Petrov and André Lichnerowicz, Pirani explained more clearly than had previously been possible the central role played by the Riemann tensor and in particular the tidal tensor in general relativity.
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HD 113766 is a binary star system located 424 light years from Earth in the direction of the constellation Centaurus. The star system is approximately 10 million years old and both stars are slightly more massive than our sun. The two are separated by an angle of 1.3 arcseconds, which, at the distance of this system, corresponds to a projected separation of at least 170 AU. What makes HD 113766 special is the presence of a large belt of warm (~440 K) dust surrounding the star HD 113766 A. The dense dust belt, more than 100 times more massive than our own asteroid belt, is thought to be collapsing to form a rocky planet, which when it has formed will lie within the star's terrestrial habitable zone where liquid water can exist on its surface. HD 113766 represents the most well understood system in a growing class of objects that should provide more clues to how rocky planets like the Earth formed.
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Located 163 ± 4 light-years away, it is an orange giant star of spectral type K0III that is 1.0–1.4 times as massive as the Sun. An ageing star, it has cooled and expanded to times the Sun's radius. It is radiating as much power as the Sun from its outer envelope at an effective temperature of . Traditionally called Alkes "the cup", and marking the base of the cup is Alpha Crateris, an orange- hued star of magnitude 4.1, that is 141 ± 2 light-years from the Sun. With an estimated mass 1.75 ± 0.24 times that of the Sun, it has exhausted its core hydrogen and expanded to 13.2 ± 0.55 times the Sun's diameter, shining with 69 times its luminosity and an effective temperature of around 4600 K. With a magnitude of 4.5, Beta Crateris is a binary star system, consisting of a white-hued giant star of spectral type A1III and a white dwarf of spectral type DA1.4, 296 ± 8 light-years from the Sun.
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Theta Muscae is a triple star system thought to be around 7,500 light-years distant. It consists of a spectroscopic binary system composed of the Wolf–Rayet star (spectral type: WC5 or 6) and an O-type main-sequence star (spectral type: O6 or O7) that orbit each other every 19 days and a blue supergiant (spectral type: O9.5/B0Iab) set about 46 milliarcseconds apart from them. If the system's estimated distance from Earth is accurate, the binary stars are about 0.5 astronomical units (AU) apart and the supergiant about 100 AU apart from them. All three are highly luminous; combined, they are likely to be over a million times as luminous as the Sun. TU Muscae is a binary star system located around 15,500 light-years away made up of two hot, luminous, blue main-sequence stars of spectral types O7.5V and O9.5V, with masses 23 and 15 times that of the Sun.
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Polar variables are magnetic white dwarfs accreting material from a low mass donor, with no accretion disk due to the intense magnetic field A Polar is a highly magnetic type of cataclysmic variable binary star system, originally known as an AM Herculis star after the prototype member AM Herculis. Like other cataclysmic variables (CVs), polars contain two stars: an accreting white dwarf (WD), and a low-mass donor star (usually a red dwarf) which is transferring mass to the WD as a result of the WD's gravitational pull, overflowing its Roche lobe. Polars are distinguished from other CVs by the presence of a very strong magnetic field in the WD. Typical magnetic field strengths of polar systems are 10 million to 80 million gauss (1000-8000 teslas). The WD in the polar AN Ursae Majoris has the strongest known magnetic field among cataclysmic variables, with a field strength of 230 million gauss (23 kT).
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Professor William Wallace Campbell of the Lick Observatory announced that Capella was binary in 1899, based on spectroscopic observations—he noted on photographic plates taken from August 1896 to February 1897 that a second spectrum appeared superimposed over the first, and that there was a doppler shift to violet in September and October and to red in November and February—showing that the components were moving toward and away from the Earth (and hence orbiting each other). Almost simultaneously, British astronomer Hugh Newall had observed its composite spectrum with a four prism spectroscope attached to a telescope at Cambridge in July 1899, concluding that it was a binary star system. Many observers tried to discern the component stars without success. Known as "The Interferometrist's Friend", it was first resolved interferometrically in 1919 by John Anderson and Francis Pease at Mount Wilson Observatory, who published an orbit in 1920 based on their observations.
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An even more luminous yet closer star, WR 25, appears to be most likely to the title. Another nearer star, Eta Carinae, which was the second-brightest star in the sky for a few years in the 19th century, appears to be slightly more luminous than WR 102ka, but is known to be a binary star system. There is also the more recently discovered Pistol Star that, like the Peony star, derives its name from the shape of the nebula in which it is embedded, and which it has probably created through heavy mass loss via fierce stellar winds and perhaps also major "mini-supernova-like" eruptions as happened to Eta Carinae around the 1830s-1840s creating the lobes observed by the Hubble Space Telescope. The luminosities of the Pistol Star, Eta Carinae, and WR 102ka are all rendered somewhat uncertain due to heavy obscuration by galactic dust in the foreground, the effects of which must be corrected for before their apparent brightness can be reduced to estimate their total radiated power or bolometric luminosity.
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The last such eclipse occurred from 2009–2011, and it is hoped that the extensive observations that will likely be carried out may yield further insights into the nature of this system. Another eclipsing binary is Beta Lyrae, which is a semidetached binary star system in the constellation of Lyra. Other interesting binaries include 61 Cygni (a binary in the constellation Cygnus, composed of two K class (orange) main-sequence stars, 61 Cygni A and 61 Cygni B, which is known for its large proper motion), Procyon (the brightest star in the constellation Canis Minor and the eighth-brightest star in the night time sky, which is a binary consisting of the main star with a faint white dwarf companion), SS Lacertae (an eclipsing binary which stopped eclipsing), V907 Sco (an eclipsing binary which stopped, restarted, then stopped again) and BG Geminorum (an eclipsing binary which is thought to contain a black hole with a K0 star in orbit around it), 2MASS J18082002−5104378 (a binary in the "thin disk" of the Milky Way, and containing one of the oldest known stars).
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In a 2017 paper, Sarah Sadavoy and Steven Stahler argued that the Sun was likely part of a binary system at the time of its formation, leading them to suggest "there probably was a Nemesis, a long time ago". Such a star would have separated from this binary system over four billion years ago, meaning it could not be responsible for the more recent perceived cycle of mass extinctions, Douglas Vakoch told Business Insider, adding that "If the sun really was part of a binary star system in its early days, its early twin deserves a benign name like Companion, rather than the threatening Nemesis." More recent theories suggest that other forces, like close passage of other stars, or the angular effect of the galactic gravity plane working against the outer solar orbital plane (Shiva Hypothesis), may be the cause of orbital perturbations of some outer Solar System objects. In 2011, Coryn Bailer-Jones analyzed craters on the surface of the Earth and reached the conclusion that the earlier findings of simple periodic patterns (implying periodic comet showers dislodged by a hypothetical Nemesis star) were statistical artifacts, and found that the crater record shows no evidence for Nemesis.
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HD 196885 is a binary star system in the northern constellation of Delphinus. It is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.39. According to its parallax of , it is located at a distance of 112 light years from the Sun. It is drifting closer with a radial velocity of −30 km/s, and is expected to come to within in 836,000 years. The absolute magnitude of the system is 3.76. The primary, component A, is an F-type main-sequence star with a stellar classification of F8V It is about two billion years old and is spinning with a projected rotational velocity, for a rotation period of around 15 days. The star has 1.33 times the mass of the Sun and 1.45 times the Sun's radius. The metallicity of this star – what astronomers term the abundance of elements with higher atomic number than helium – is nearly double that in the Sun. It is radiating 2.7 times the luminosity of the Sun from its photosphere at an effective temperature of 6,340 K. In 2004, a planet was announced to be orbiting the star in a 386-day orbit.
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Although it appears to be a single star to the naked eye, 61 Cygni is a widely separated binary star system, composed of two K class (orange) main sequence stars, the brighter 61 Cygni A and fainter 61 Cygni B, which have apparent magnitudes of 5.2 and 6.1, respectively. Both appear to be old-disk stars, with an estimated age that is older than the Sun. At a distance of just over 11 light-years, it is the 15th-nearest-known star system to the Earth (not including the Sun). 61 Cygni A is the fourth-nearest star that is visible to the naked eye for mid- latitude northern observers, after Sirius, Epsilon Eridani, and Procyon A. This system will make its closest approach at about 20,000 CE, when the separation from the Sun will be about 9 light-years. Smaller and dimmer than the Sun, 61 Cygni A has about 70 percent of a solar mass, 72 percent of its diameter and about 8.5 percent of its luminosity and 61 Cygni B has about 63 percent of a solar mass, 67 percent of its diameter, and 3.9 percent of its luminosity.
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The spinship Helix has not yet reached a suitable destination when it receives a distress signal from a binary star system. Four of the five shipboard AI (apparently formerly of the TechnoCore; in characteristic Simmons fashion, each is patterned after a famous literary figure, in this case, Japanese: Saigyo, Lady Murasaki, Ikkyu, Basho, and Ryōkan) decide that the call is worth investigating, not least because of the further anomaly that the orbital forest around the lesser of the two stars, which the AIs intend to resupply their ship from, is of neither Ouster nor Templar construction, though they may have settled on it. The AIs awaken certain crewmembers, and together they enter the system, where they are greeted by hundreds of thousands of space- adapted Ousters; they importune the Helix to save their civilization from an enormous and ancient harvester spaceship (which gathers food, air, and water), which visits every 57 years, and is so programmatically inflexible that it sees the Ouster and Templar settlements as infestations of the tree-ring, and attempts to cleanse it by eradicating them. Over the centuries, the colony's technological infrastructure has been steadily ground under by its assaults, and many die attacking or being attacked.
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