I wanted to do something more luminous and more transparent.
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Scientists estimated that it could be eight times more luminous than the actual, original moon.
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But the Pixel 4's photo was just a bit more luminous and contained sharper details.
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The result was a stellar event 10 to 100 times more luminous than your average star explosion or supernova.
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Atop these base layers the more luminous and colorful paints glisten and flow, creating a gorgeous moving nighttime landscape.
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Beginning with a dark ground and layering lighter pigments on top, the textures become less photorealistic, yet more luminous.
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Long before highlighters flooded the aisles of Sephora, makeup artists found other ways to make skin look brighter and more luminous.
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To see, in the face of change, a brighter now and an even more luminous possible future is a radical act.
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" In The Village Voice, Andrew Sarris noted that "not even Warner's has ever turned out a more luminous prison escape movie.
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A day later we're still swooning over her red carpet glow, which only grew more luminous for her subsequent tweet-worthy performance.
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If you use a more luminous foundation in photos, you can look more greasy, and certain points of you face can look higher.
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Brilliant flashes of light, more luminous and powerful than the Sun, occurring every 26 minutes and stretching as far as the eye can see.
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Federer, a six-time Australian Open champion, has seen much more luminous days in Melbourne, but he was in no mood to say farewell.
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RS Puppis is 269,000 times more luminous than our own sun, which is one reason why the gas and dust around the star are so photogenic.
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Pine's been ill-served by blandsome hero roles in the past, but he looks perfectly comfortable here as the supporting character to a more luminous lead.
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Madeline H. Caviness of the American Friends of Chartres says that the intense colors actually complement each other — the light walls make the windows more luminous.
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These canvases are nothing like his more luminous color studies, paintings so full of depth and light that it almost feels as if you can enter.
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Sure, there are formulas that virtually vanish zits and others that magically make undereyes look more luminous, but landing a singular concealer that will do both jobs?
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The six galaxies are up to 10,000 times more luminous than the Milky Way, a combination of collisions and gravitational lensing causing them to appear strange and distorted.
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Called ASASSN-15lh, the event was so bright that at one point it was 20 times more luminous than all of the stars in the Milky Way combined.
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To start, my complexion instantly became more luminous after I smoothed the formula over my skin — though, admittedly, that's an instant effect that loads of face oils bring.
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Though I must say, when I compared a G33 preview unit against a Galaxy S9+, with both phones set to auto brightness on max, the S9's display appeared noticeably more luminous.
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I wanted to see if the re-size function could make my hair appear thicker and more luminous, and I also wanted to add a sensual filter to show off my alternative edge.
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Ali's wit grew only quicker and more luminous until it was quieted by Parkinson's disease, and his commitment to telling tough truths (even if, in this case, the truth was exaggerated) only deepened.
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So Nelson used NASA's satellite images from 2012 and 2016 and calculated the difference in light pixels to see which areas of the world had grown more luminous and which areas went dark.
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This brings us to his partner Amy Klobuchar, who might seem like a strange choice when you consider that the Democratic bench has more luminous figures like Kamala Harris, Cory Booker, and Elizabeth Warren.
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I put the recommended four to six drops onto my face alone or under a moisturizer, and my dry combination skin was softer, more luminous, and noticeably better hydrated without ever drifting into oily territory.
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Fresh just came out with the Black Tea Kombucha Facial Treatment Essence, a potent antioxidant solution that uses fermented black tea, another K-beauty staple, to leave skin smooth, hydrated, and more luminous over time.
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Another serum with a relatively high dosage of vitamin C, the Korres formula contains 15% of the antioxidant, which helps to tone down the appearances of spots, while brightening your overall skin tone for a more luminous glow.
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Beloved by her teammates as a fussy, bright-eyed darling, Ruth—who, like Debbie, believes that "it's never easy" for her—that her life is plagued by false starts and misadventure—basks in the glow of success, all the more luminous for the shadow at her back, where the underdogs of GLOW stand and patiently abide.
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The star is about twice as massive as our own sun and ten times more luminous, according to Dr. Li. Drawing on data from the European Space Agency's Gaia spacecraft, which has charted the positions and motions of some 1.3 billion stars in the Milky Way, the astronomers traced the streaking star back to the galactic center.
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These kinds of black holes are found at the core of large galaxies, and supermassive black holes are kind of all over the place, but what makes this one unique is its insane size and luminosity: It has a mass of 100,000 times that of the Sun, and is ten times more luminous than the brightest X-ray source ever seen.
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A Chandra X-ray image of Sirius A and B shows Sirius B to be more luminous than Sirius A. Whereas in the visual range, Sirius A is the more luminous.
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With a light curve that maximised 14-47 days after the initial observation, it was three times more luminous than SN 1991T (which was, at the time of its 1991 discovery, the brightest Ia supernova on record), 1.5 times more luminous than SN 2002ic, and close to 100 times more luminous than previously thought possible. Scientists Denis Leahy and Rachid Ouyed from the University of Calgary contend that the incidence of a quark nova, a very luminous process involving the degeneration of neutrons into their constituent quarks, could explain the unusual magnitude of the luminosity.
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Although cooler than the sun, its larger size means that it is more luminous, emitting in total 217 times as much electromagnetic radiation.
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The WR component is five times the radius of the sun, but its high temperature means it is over 100,000 times more luminous. Its mass is determined from the orbital motion to be . The O star is larger at , more luminous at , and more massive at . Although the stars are only separated by around , they are well separated because of their small size.
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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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Thuban has a spectral class of A0III, indicating its similarity to Vega in temperature and spectrum, but more luminous and more massive. It has been used as an MK spectral standard for the A0III type. Thuban is not a main sequence star; it has now ceased hydrogen fusion in its core. That makes it a white giant star, being 120 times more luminous than the Sun.
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Some semiregular and irregular variables are less luminous giant stars, while others are more luminous supergiants including some of the largest known stars such as VY CMa.
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When their core helium is eventually exhausted, they progress to helium shell burning on the asymptotic giant branch (AGB). On the AGB they become cooler and much more luminous.
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Its mass is about , with a surface temperature of 125,000 ± 5,000 K. Currently it is 200 times more luminous than the Sun, but its apparent magnitude is only +15.75.
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The probable causes are the proximity to a parent star that is 3–4 times more luminous than the Sun as well as the internal heat within the planet.
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The side panels have similar characteristics, but are set in more luminous landscapes, with the elements in the background becoming increasingly invisible in the haze, according to aerial perspective.
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B-type subdwarfs, being more luminous than white dwarfs, are a significant component in the hot star population of old stellar systems, such as globular clusters and elliptical galaxies.
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This produced a golden reflection emanating from in between the tesserae as well as their front, causing a far richer and more luminous effect than even plain gold leaf would create.
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The star is six times more luminous than the Sun, 1.6 times its radius, and has an surface temperature of . It has exhausted its core hydrogen and evolved away from the main sequence.
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The luminosity has increased in a nearly linear fashion to the present, rising by 1% every 110 million years. Likewise, in three billion years the Sun is expected to be 33% more luminous. The hydrogen fuel at the core will finally be exhausted in five billion years, when the Sun will be 67% more luminous than at present. Thereafter the Sun will continue to burn hydrogen in a shell surrounding its core, until the luminosity reaches 121% above the present value.
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The star is cooler, more luminous, similar mass, and larger than our Sun. This star is 22% older than our Sun and with metallicity nearly doubled with the Sun, based on its abundance of iron.
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Orion's Belt or The Belt of Orion is an asterism within the constellation. It consists of the three bright stars Zeta (Alnitak), Epsilon (Alnilam), and Delta (Mintaka). Alnitak is around 800 light years away from earth and is 100,000 times more luminous than the Sun; much of its radiation is in the ultraviolet range, which the human eye cannot see. Alnilam is approximately 1340 light years away from Earth, shines with magnitude 1.70, and with ultraviolet light is 375,000 times more luminous than the Sun.
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Mintaka (δ Orionis) is 1,200 light-years away and shines with magnitude 2.21. Mintaka is 90,000 times more luminous than the Sun. Mintaka is a double star. The two stars orbit around each other every 5.73 days.
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Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major. A member of the M81 Group, it is about five times more luminous than the whole Milky Way and has a center one hundred times more luminous than our galaxy's center. The starburst activity is thought to have been triggered by interaction with neighboring galaxy M81. As the closest starburst galaxy to Earth, M82 is the prototypical example of this galaxy type.
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HD 159868 is a yellow dwarf star approximately 182.5 light-years away in the constellation of Scorpius. The star is thought to be 3.05 times more luminous than the Sun, yet the metallicity is identical to the Sun.
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Red- giant-branch stars have an inert helium core surrounded by a shell of hydrogen fusing via the CNO cycle. They are K- and M-class stars much larger and more luminous than main-sequence stars of the same temperature.
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They lie near the instability strip, cooler than type I Cepheids more luminous than type II Cepheids. Their pulsations are caused by the same basic mechanisms related to helium opacity, but they are at a very different stage of their lives.
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The last stars in the list are familiar nearby stars put there for comparison, and not among the most luminous known. It may also interest the reader to know that the Sun is more luminous than approximately 95% of all known stars in the local neighbourhood (out to, say, a few hundred light years), due to enormous numbers of somewhat less massive stars that are cooler and often much less luminous. For perspective, the overall range of stellar luminosities runs from dwarfs less than 1/10,000th as luminous as the Sun to supergiants over 1,000,000 times more luminous.
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The title supergiant, as applied to a star, does not have a single concrete definition. The term giant star was first coined by Hertzsprung when it became apparent that the majority of stars fell into two distinct regions of the Hertzsprung–Russell diagram. One region contained larger and more luminous stars of spectral types A to M and received the name giant. Subsequently, as they lacked any measurable parallax, it became apparent that some of these stars were significantly larger and more luminous than the bulk, and the term super-giant arose, quickly adopted as supergiant.
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As their hydrogen shells continue to produce more helium, the cores of RGB stars increase in mass and temperature. This causes the hydrogen shell to fuse more rapidly. Stars become more luminous, larger, and somewhat cooler. They are described as ascending the RGB.
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Alphard , designated Alpha Hydrae (α Hydrae, abbreviated Alpha Hya, α Hya), is the brightest star in the constellation of Hydra. It is a single giant star, cooler than the sun but larger and more luminous. It is about 177 light years away.
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18 Delphini has a spectral type of G6III and is a red clump giant, an evolved star that is burning helium in its core. It has a temperature of 4979 K, is 8.5 times larger than the sun and 40 times more luminous. It has a current mass of .
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More luminous Cepheids are cooler and larger and have longer periods. Along with the temperature changes their radii also change during each pulsation (e.g. by ~25% for the longer-period l Car), resulting in brightness variations up to two magnitudes. The brightness changes are more pronounced at shorter wavelengths.
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SDSS J0100+2802 is about four times more luminous than SDSS J1148+5251, and seven times more luminous than ULAS J1120+0641, the most distant quasar known, although it is only less than fourth as luminous as HS 1946+7658, the most luminous quasar known. It harbors a black hole with mass of 12 billion solar masses (estimated according to MgII emission line correlations). This makes it one of the most massive black holes discovered so early in the universe, although it is only less than one fifth as massive as TON 618, the most massive black hole known. The diameter of this black hole is about 70.9 billion kilometres, seven times the diameter of Pluto's orbit.
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HD 88133 is an 8th magnitude star in the constellation of Leo. It is classified as a yellow subgiant star (spectral type G5IV). It is slightly more massive than our Sun, cooler and more luminous. As a subgiant, it has left the main sequence and started to evolve towards red gianthood.
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28 Aurigae (28 Aur) is a star in the constellation Auriga. Its apparent magnitude is 6.80. It is a giant star which has exhausted its core hydrogen and expanded to ten times the size of the Sun. Despite being slightly cooler than the sun at it is 73 times more luminous.
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HD 185269 is a stellar triple system approximately 170 light-years away in the constellation Cygnus. It is easily visible to binoculars, but not the naked eye. The primary star is a third more massive and four times more luminous than the Sun. The spectrum of the star is G0IV.
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A yellow supergiant (YSG) is a star, generally of spectral type F or G, having a supergiant luminosity class (e.g. Ia or Ib). They are stars that have evolved away from the main sequence, expanding and becoming more luminous. Yellow supergiants are smaller than red supergiants; naked eye examples include Polaris.
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The minimum masses are found to be and respectively for the primary and secondary. With the assumption of an inclination of 60°, the actual masses are and . The secondary is more massive and visually brighter, but not more luminous. Both components of AB7 have powerful stellar winds and are losing mass rapidly.
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As this kind of star is more luminous than the previous red dwarf, planets orbiting it that were frozen during the former stage could be thawed during the several billions of years this evolutionary stage lasts (5 billion years, for example, for a star), giving life an opportunity to appear and evolve.
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The primary star is an early G-type subgiant star. It has a mass 1.61 times that of the Sun, and is 6.8 times more luminous. The companion star regularly perturbs the G-type primary star primary, causing it to wobble around the barycenter. From this, an orbital period of 45 years has been calculated.
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Coronal stars are ubiquitous among the stars in the cool half of the Hertzsprung–Russell diagram. These coronae can be detected using X-ray telescopes. Some stellar coronae, particularly in young stars, are much more luminous than the Sun's. For example, FK Comae Berenices is the prototype for the FK Com class of variable star.
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VFTS 682 is a Wolf–Rayet star in the Large Magellanic Cloud. It is located over north-east of the massive cluster R136 in the Tarantula Nebula. It is 150 times the mass of the sun and 3.2 million times more luminous which makes it one of the most massive and most luminous stars known.
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NGC 5806 contains a star that was catalogued as a supernova (SN Hunt 248), but turned out to be a supernova imposter. The progenitor was detected as a cool hypergiant with an absolute visual magnitude of −9 and 400,000 times more luminous than the sun. The eruption saw it increase in luminosity to around .
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Narendranath first experienced Nirvikalpa Samadhi at Cossipore Garden House in Calcutta. One evening when he was meditating with his friend Gopal (senior), he suddenly felt a light behind his head. As he concentrated on the light, it became more luminous. Narendra concentrated further on the light and found it getting subsumed in to "the Absolute".
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In fact, its properties are similar to an electric arc. The leader tapers and branches into thousands of thinner, cooler, hair-like discharges (called streamers). The streamers look like a bluish 'haze' at the ends of the more luminous leaders. The streamers transfer charge between the leaders and toroid to nearby space charge regions.
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Around 1920, Iosif Iser adopted a more luminous range of colours, while softening the textures. He continued his "Tatar" themes with his Tătăroaică în albastru ("Tatar Woman in Blue") and Famile de tătari ("Tatar Family"). He expanded on another series, one that depicted harlequins. In 1955, he was elected a full member of the Romanian Academy.
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The two stars are estimated to have masses of and respectively. The primary is over five hundred times more luminous than the sun. The system shows signs of hot coronal activity, although the primary star is too cool for this. It may originate on the secondary, possibly as material is accreted from the cool giant primary.
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The spectral type for 21 Camelopardalis is given only as A5 with no published luminosity class. It is treated as a normal main sequence star, although it is calculated to be larger and more luminous than a typical A5 main sequence star. Based upon changes to its proper motion over time, this is a probable astrometric binary.
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Subdwarf B stars, being more luminous than white dwarfs, are a significant component in the hot star population of old stellar systems, such as globular clusters, spiral galaxy bulges and elliptical galaxies. They are prominent on ultraviolet images. The hot subdwarfs are proposed to be the cause of the UV upturn in the light output of elliptical galaxies.
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This class of sources are also known as edge-brightened and are more luminous than their counterparts, with bright hotspots at the ends of their lobes. The jets are often one-sided due to relativistic beaming. VLA map of the FR-II quasar 3C 47 at 4.9 GHz. G is the core, A the jetted hotspot.
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Kepler-452b orbits its host star with an orbital period of 385 days and an orbital radius of about 1.04 AU, nearly the same as Earth's (1 AU). Kepler-452b is most likely not tidally locked and has a circular orbit. Its host star, Kepler-452, is about 20% more luminous than the Sun (L = 1.2 )..
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Alnilam (ε Orionis) is a supergiant, approximately 2,000 light-years away from Earth and magnitude 1.70. It is the 29th-brightest star in the sky and the fourth-brightest in Orion. It is 375,000 times more luminous than the Sun. Its spectrum serves as one of the stable anchor points by which other stars are classified.
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One can also use stencil buffer like with the shadow volume technique. Another technique can also be used to provide usually satisfying, if inaccurate volumetric lighting effects. The algorithm functions by blurring luminous objects away from the center of the main light source. Generally, the transparency is progressively reduced with each blur step, especially in more luminous scenes.
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Zeta Tucanae (ζ Tuc, ζ Tucanae) is a star in the constellation Tucana. It is a spectral class F9.5 main sequence star with an apparent magnitude of +4.23. Despite having a slightly lower mass, this star is more luminous than the Sun. Based upon parallax measurements by the Hipparcos spacecraft, it is approximately 28.0 light years from Earth.
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A star remains near its initial position on the main sequence until a significant amount of hydrogen in the core has been consumed, then begins to evolve into a more luminous star. (On the HR diagram, the evolving star moves up and to the right of the main sequence.) Thus the main sequence represents the primary hydrogen-burning stage of a star's lifetime.
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On this basis it is calculated to have a mass of , a luminosity of , and an age around two billion years. Its surface temperature is 4645 K. Or it might be a red-giant branch star, still fusing hydrogen in a shell around an insert helium core, in which case it would be slightly less massive, older, cooler, larger, and more luminous.
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HD 208487 is a 7th magnitude G-type main sequence star located approximately 144 light-years away in the constellation of Grus. It has the same spectral type as our sun, G2V. However, it is probably slightly less massive and more luminous, indicating that it is slightly older. As of 2008, there is one known extrasolar planet confirmed to be orbiting the star.
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HD 10647 (q1 Eridani) is a 6th-magnitude yellow-white dwarf star, 57 light- years away in the constellation of Eridanus. The star is visible to the unaided eye under very dark skies. It is slightly hotter and more luminous than the Sun, and at 1,750 million years old, it is also younger. An extrasolar planet was discovered orbiting this star in 2003.
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Classification of the spectrum is difficult due to the peculiarities. An MK classification of 15 UMa using the calcium K line is A3 V, but using metallic spectral lines it can appear as a cooler and more luminous star. Spectral lines in the blue region give a classification of F5 Ib, while in the violet region the lines suggest F5 III/IV.
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However, the eastern limb of the nebula is 50% more luminous than the western limb. Additionally, irregularities in the surface brightness are seen across the face of the shell. The source of the east–west asymmetry is not known but it could be related to the offset of the central star. The central star is classified as a subdwarf O star.
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The X-ray luminosity of Epsilon Eridani is about (). It is more luminous in X-rays than the Sun at peak activity. The source for this strong X-ray emission is Epsilon Eridani's hot corona. Epsilon Eridani's corona appears larger and hotter than the Sun's, with a temperature of , measured from observation of the corona's ultraviolet and X-ray emission.
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Both members of the binary are low-mass objects still contracting towards the main sequence. Comparison with theoretical evolutionary tracks gives them ages of one Myr or less. However, the primary is more luminous than expected even for this age and it may be younger than the secondary. The primary has a temperature of , a radius of , and a bolometric luminosity of .
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Despite having a slightly lower mass, this star is more luminous than the Sun. The composition and mass of this star are very similar to the Sun, with a slightly lower mass and an estimated age of three billion years. The solar- like qualities make it a target of interest for investigating the possible existence of a life-bearing planet.
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It is still substantially more luminous than nearby quasars such as 3C 273\. Quasars were much more common in the early universe than they are today. This discovery by Maarten Schmidt in 1967 was early strong evidence against Steady-state cosmology and in favor of the Big Bang cosmology. Quasars show the locations where massive black holes are growing rapidly (by accretion).
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In addition, WASP-15 is most likely younger than the Sun, as it has an estimated age of 3.9 billion years. WASP-15 is approximately 3.09 times more luminous than the Sun. WASP-15 is located at a distance of approximately 290 parsecs (900 light years), and it has an estimated apparent magnitude of 10.9. It is, thus, not visible from Earth with the unaided eye.
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1 Serpentis (1 Ser) is a red giant in the constellation Virgo with an apparent magnitude of 5.52. It is a red clump giant, a cool horizontal branch star that is fusing helium in its core. It has expanded to over 13 times the radius of the Sun and although it is cooler at it is 77 times more luminous. It is 322 light years away.
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OGLE-TR-132 is a distant magnitude 15.72 star in the star fields of the constellation Carina. Because of its great distance, about 4,900 light-years, and location in the crowded field it was not notable in any way. The spectral type of the star is type F. A yellow-white, very metal-rich dwarf star, it is slightly hotter and more luminous than the Sun.
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The prominence plasma is typically a hundred times more luminous and denser than the coronal plasma. A prominence forms over timescales of about a day and may persist in the corona for several weeks or months, looping hundreds of thousands of miles into space. Some prominences break apart and may then give rise to coronal mass ejections. Scientists are currently researching how and why prominences are formed.
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Based on the Gaia distance, 7 Cancri has a bolometric luminosity 65 times that of the sun. Its temperature, based on its colour, is calculated to be and the resulting radius is . 7 Cancri is a cool giant star. It has evolved away from the main sequence after exhausting its core hydrogen and expanded so that it is larger and more luminous than the sun, although cooler.
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M59-UCD3 is approximately the same size as M60-UCD1 with a half-light radius, rh, of approximately 20 parsecs but is 40% more luminous with an absolute visual magnitude of approximately −14.6. This makes M59-UCD3 the densest known galaxy. Based on stellar orbital velocities, two UCD in the Virgo Cluster are claimed to have supermassive black holes weighing 13% and 18% of the galaxies' masses.
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A second candidate was announced in 2011. Messier 49 was the first member of the Virgo Cluster of galaxies to be discovered. It is the most luminous member of that cluster and more luminous than any galaxy closer to the Earth. This galaxy forms part of the smaller Virgo B subcluster located 4.5° away from the dynamic center of the Virgo Cluster, centered on Messier 87.
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For example, the period has changed on average by about 144.7 s per year, but has sometimes remained constant for several years. RS Puppis is considered to be a long-period Cepheid because it has a period longer than 10 days. The only nearer long-period Cepheid is l Carinae. Cepheids closely follow a period-luminosity relationship, with more luminous stars having longer periods.
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The host galaxy for ASASSN-15lh is APMUKS(BJ) B215839.70−615403.9, much larger and more luminous than the Milky Way. The host galaxy has visual magnitude 18.5 and is red in color with a low rate of star formation. It maintained a steady brightness until the supernova lit up. The strongest parts of the galaxy's spectrum have wavelengths around 1 μm in the near infrared.
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The luminosity then became more or less stable until 1992. As the star cooled and became more luminous, its radius increased from around in 1900 to about by 1992. When the star faded in 1992, it was obscured by dust formation and comparisons of temperature and luminosity became more difficult. The visual luminosity dropped by about five magnitudes, but the infrared brightness increased by a comparable amount.
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Evolutionary tracks on the HR diagram. The 15 and 60 tracks are typical of massive O-type stars. In the lifecycle of O-type stars, different metallicities and rotation rates introduce considerable variation in their evolution, but the basics remain the same. O-type stars start to move slowly from the zero-age main sequence almost immediately, gradually becoming cooler and slightly more luminous.
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The SagDIG is thought to be the member of the Local Group most remote from the Local Group's barycenter. It is only slightly outside the zero-velocity surface of the Local Group. SagDIG is a much more luminous galaxy than Aquarius Dwarf and it has been through a prolonged star formationMomany et al. 2005. This has resulted in it containing a rich intermediate-age population of stars.
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M33-013406.63, also known as B416, is a blue supergiant star in the constellation of Triangulum. It is located within the Triangulum Galaxy, which is approximately 2,380,000–3,070,000 light years away from Earth. It is the most luminous star ever discovered and one of the largest stars in the Triangulum Galaxy. It is estimated to be approximately 6,400,000–10,280,000 times more luminous than the Sun.
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Alpha Cancri is a fourth-magnitude star with an apparent magnitude of 4.20, making it barely visible to the naked eye under good lighting conditions. Nevertheless, it is 23 times more luminous than the Sun. Its stellar classification is A5m. The distance of Alpha Cancri calculated from the Gaia Data Release 2 parallax is roughly 50 parsecs from Earth, or approximately 164 light years away.
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Somewhat more luminous than it should be for its surface temperature, 51 Eridani has also been classified as spectral type F0IV—a type corresponding to ageing stars that have used up their core hydrogen fuel and become subgiants—however in this case it is a phenomenon of very young stars 5 to 30 million years old that have yet to settle on the main sequence.
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Their stellar classification is nearly identical to that of the Sun. ζ1 has 96% of the Sun's mass and 84% of the Sun's radius. ζ2 is slightly larger and more luminous than ζ1, with 99% of the Sun's mass and 88% of the Sun's radius. The two stars are somewhat deficient in metals, having only 60% of the proportion of elements other than hydrogen and helium as compared to the Sun.
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HD 179949 is a 6th magnitude star in the constellation of Sagittarius. It is a yellow-white dwarf (spectral class F8 V), a type of star hotter and more luminous than our Sun. The star is located about 90 light years from Earth and might be visible under exceptionally good conditions to an experienced observer without technical aid; usually binoculars are needed. The star HD 179949 is named Gumala.
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Considering only this last parameter, Gliese 686 is considerably brighter than other known red dwarfs; thus, it is 6.5 times more luminous than Ross 154 and 15 times more than Proxima Centauri, the closest star to the Solar System. Gliese 686 has a radius approximately equal to half the solar radius. Its projected rotation speed is 2.5 km / s, its rotation period being equal to or less than 10.3 days.
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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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From Hipparcos data, its proper motion is seen to be discrepant and accelerating, although there is insufficient data to determine any orbit. Q Scorpii is cooler than the sun, but more luminous. It is a red clump giant, at the cool end of the horizontal branch, fusing helium in its core. Like all red clump giants, it has an effective temperature near and a bolometric luminosity of around .
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On 19 and 20 June 2010 a project was announced ( the Projet Créteil Cathédrale+) to bring about the transformation of the present modest cathedral building into a more welcoming, more luminous and more visible symbol of the presence of the Church in Val-de-Marne. The permission of the Holy See having been obtained, the project is under way, and the estimated end of the building works is September 2013.
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The relevance of the artists is in their work and in their talent. There is no greater value. The state must open the field to those who agree with the government and those who do not, that is the challenge when it comes to making public policies." He added: "Our vision poses a much more luminous, open, plural and diverse scenario to several orientations of the world, that enrich one another.
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This is a single- lined spectroscopic binary system, but the secondary has been detected using interferometry. It is a RS Canum Venaticorum variable system with eclipses. The total amplitude of variation is only about a thousandth of a magnitude. The secondary star is similar to the sun, presumably a main sequence star, while the primary is a giant star 25 times larger than the sun and two hundred times more luminous.
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The Grisly Wife is a 1993 Miles Franklin literary award-winning novel by the Australian author Rodney Hall. The Miles Franklin Award Judges' Report called it "a novel with a rather surprising vision." Miles Franklin Award Judges' Report This novel is the third book in The Yandilli Trilogy (also referred to as A Dream More Luminous Than Love), following the novels Captivity Captive in 1988, and The Second Bridgeroom in 1991.
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R136a3 is a Wolf–Rayet star in R136, a massive star cluster located in Dorado. It is located near R136a1, the most massive and luminous star known. R136a3 is itself one of the most massive and most luminous stars known at 180 times more massive and 3.8 million times more luminous than the Sun. The formal name of the star is RMC 136a3, standing for Radcliffe observatory, Magellanic Clouds, 136a3.
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It is rotating rapidly, with the projected rotational velocity of providing a lower limit on the azimuthal velocity along the star's equator. This is classified as a shell star that has a circumstellar disk of gas around the star's equator, which may be causing it to vary in magnitude. It is 1100 times more luminous than the Sun, and possesses a radius 15 times that of the Sun.
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The two system components A and B are both A-type main sequence stars, hotter, larger, and more luminous than the Sun. The primary is spinning rapidly and the secondary relatively slowly. The primary has a mass of , an effective temperature of , a radius of , and a bolometric luminosity of . The secondary has a mass of , an effective temperature of , a radius of , and a bolometric luminosity of .
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It is twice as massive and 3.3 times as wide as our sun and 26 times more luminous. A line drawn between Alpha Hydri and Beta Centauri is bisected by the south celestial pole. In the southeastern corner of the constellation is Gamma Hydri, a red giant of spectral type M2III located 214 light-years from Earth. It is a semi-regular variable star, pulsating between magnitudes 3.26 and 3.33.
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Alpha Comae Berenices (α Comae Berenices, abbreviated Alpha Com, α Com) is a binary star in the constellation of Coma Berenices (Berenice's Hair), away. It consists of two main sequence stars, each a little hotter and more luminous than the Sun. Alpha Comae Berenices is said to represent the crown worn by Queen Berenice. The two components are designated Alpha Comae Berenices A (officially named Diadem , the traditional name for the system) and B.
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NGC 4565 is a giant spiral galaxy more luminous than the Andromeda Galaxy.Globular Cluster Systems in Galaxies Beyond the Local Group Much speculation exists in literature as to the nature of the central bulge. In the absence of clear-cut dynamical data on the motions of stars in the bulge, the photometric data alone cannot adjudge among various options put forth. However, its exponential shape suggested that it is a barred spiral galaxy.
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Cepheid variables may pulsate in a fundamental mode, the first overtone, or rarely a mixed mode. Pulsations in an overtone higher than first are rare but interesting. The majority of classical Cepheids are thought to be fundamental mode pulsators, although it is not easy to distinguish the mode from the shape of the light curve. Stars pulsating in an overtone are more luminous and larger than a fundamental mode pulsator with the same period.
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Above a certain mass, depending on metallicity, red supergiants will evolve back to blue supergiants rather than execute a blue loop, but they will do so as unstable yellow hypergiants rather than regularly pulsating Cepheid variables. Very massive stars never cool sufficiently to reach the instability strip and do not ever become Cepheids. At low metallicity, for example in the Magellanic Clouds, stars can retain more mass and become more luminous Cepheids with longer periods.
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It is not known if Kepler-452b is a rocky planet but based on its small radius, Kepler-452b is likely to be rocky. It is not clear if Kepler-452b offers habitable environments. It orbits a G2V-type star, like the Sun, which is 20% more luminous, with nearly the same temperature and mass. However, the star is 6.5 billion years old, making it 1.9 billion years older than the Sun.
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The more luminous member is a B-type main-sequence star with a stellar classification of B9V. Its fainter companion is an F-type main-sequence star with a class of F0Vn, where the 'n' suffix indicates that the metal absorption lines in its spectrum are unusual broad ("nebulous") and indicative of rapid rotation. Based upon discrepancies in the proper motion measurements, there are hints of a third member of this system.
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HD 73526 c is an extrasolar planet orbiting about 97 million miles (1.05 AU) away from its parent star. Based on its mass, this planet is likely to be a gas giant. At the distance this planet orbits from its star, which is more luminous than our Sun, HD 73526 c would receive insolation 84% that of Venus. HD 73526 c is in a 2:1 orbital resonance with HD 73526 b.
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HD 139139 (also known as EPIC 249706694) is likely part of a bound pair system of main sequence stars about away from Earth in the constellation Libra. HD 139139 is a G-type main-sequence star, a little larger and more luminous than the sun, and at an almost identical temperature. It has an apparent magnitude of 9.8. The companion star is thought to be a K5-7 red dwarf away from HD 139139\.
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The hun is virile, independent and perpetual, and as such it never allows itself to be limited in matter. Otherwise said, the po is the "earthly" (di) soul that goes downward, while the hun is the "heavenly" (tian) soul that moves upward. To extend life to its full potential the human shen must be cultivated, resulting in ever clearer, more luminous states of being. It can transform in the pure intelligent breath of deities.
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Hertzsprung–Russell diagram for globular cluster M5. The red-giant branch runs from the thin horizontal subgiant branch to the top right, with a number of the more luminous RGB stars marked in red. The red-giant branch (RGB), sometimes called the first giant branch, is the portion of the giant branch before helium ignition occurs in the course of stellar evolution. It is a stage that follows the main sequence for low- to intermediate-mass stars.
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Hydroxyl megamasers occur in the nuclear regions of LIRGs, and appear to be a marker in the stage of the formation of galaxies. As hydroxyl emission is not subject to extinction by interstellar dust in its host LIRG, hydroxyl masers may be useful probes of the conditions where star formation in LIRGs takes place.Darling (2005), p. 217. At redshifts of z ~ 2, there are LIRG-like galaxies more luminous than the ones in the nearby universe.
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The observed relationship between the hydroxyl luminosity and far infrared luminosity suggests that hydroxyl megamasers in such galaxies may be tens to hundreds of times more luminous than observed hydroxyl megamasers.Burdyuzha and Komberg (1990) Detection of hydroxyl megamasers in such galaxies would allow precise determination of the redshift, and aid understanding of star formation in these objects.Lo (2005), pp. 656–657. The first detection of the Zeeman effect in another galaxy was made through observations of hydroxyl megamasers.
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Epsilon Leonis has a stellar classification of G1 II, with the luminosity class of II indicating that, at an age of , it has evolved into a bright giant. It is much larger and brighter than the Sun with a luminosity 288 times and a radius 21 times solar. Consequently, its absolute magnitude is actually –1.49, making it one of the more luminous stars in the constellation, significantly more than Regulus. Its apparent brightness, though, is only 2.98.
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RT Carinae, also known as CD-58 3538, is a variable star in the Carina Nebula in the constellation Carina. It has a mean apparent magnitude of +8.55. RT Carinae is a red supergiant with a spectral type of M2+ Iab and has a temperature of 3,660 K. With a diameter 861 times that of the Sun, it is one of the largest stars known. The luminosity is estimated to be 120,000 times more luminous than the Sun.
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9 Pegasi (9 Peg) is a star in the constellation Pegasus. Its apparent magnitude is 4.35. 9 Pegasi is defined and used as an MK standard star for the spectral type G5 Ib. It is a yellow supergiant nearly two thousand times more luminous than the sun and sixty times larger. It has been reported to be slightly variable and is listed in the New Catalogue of Suspected Variable Stars with a magnitude range of 4.20 to 4.35.
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In so doing, the phosphor is excited by the electrical energy and fluoresces producing visible light. Like plasma globes, crackle tubes respond to touch; the filaments appear to be "attracted" toward the point of contact and usually become more luminous (brighter) as the electricity is grounded. The tubes are also filled with a noble gas like neon, argon, or xenon which acts as the electron transfer medium of the cavity. The gas is typically below atmospheric pressure.
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The band of White dwarfs has three separate regions types of variable: DOV, DBV, and DAV (= ZZ Ceti variables) white dwarfs. Each of these types of pulsating variable has an associated instability strip created by variable opacity partial ionisation regions other than helium. Most high luminosity supergiants are somewhat variable, including the Alpha Cygni variables. In the specific region of more luminous stars above the instability strip are found the yellow hypergiants which have irregular pulsations and eruptions.
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HR Carinae has a temperature around 21,000K when quiescent and the spectrum is of an early B hypergiant, but in outburst it cools to below 8,000K. HR Carinae is a lot like Eta Carinae, both luminous blue variables, and both surrounded by ejected material. HR Carinae is also likely to be a binary system with a similar separation, period, and ratio of component sizes to Eta Carinae. However, the Eta Carinae system is more massive and more luminous.
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S Vulpeculae is now confirmed as a classical Cepheid variable with one of the longest known periods at 68 days, although the period has changed several times. As such, it is also one of the cooler and more luminous of the Cepheids, and it lies close to the zone where semiregular variable stars are found. The shape and amplitude of the light curve varies significantly from cycle to cycle and secularly. The apparent magnitude ranges from 8.69 to 9.42.
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The emission lines are generated in the stellar wind and the photosphere is completely hidden. The surface fraction of hydrogen is still estimated to be around 60%. HD 97950B is the most massive and most luminous star known in the NGC 3603 region, nearly three million times more luminous than the sun and 132 times more massive. Although the star is very young, around 1.5 million years old, it has already lost a considerable fraction of its initial masses.
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RS Puppis is a supergiant and Classical Cepheid variable. While most supergiants such as Alpha Cygni variables, semiregular variables, and irregular variables show some degree of photometric variability, certain types of variables amongst the supergiants are well defined. The instability strip crosses the region of supergiants, and specifically many yellow supergiants are Classical Cepheid variables. The same region of instability extends to include the even more luminous yellow hypergiants, an extremely rare and short-lived class of luminous supergiant.
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The overall appearance of α Equulei is a G-type giant with an apparent magnitude of +3.92, but it is a spectroscopic binary consisting of two individual stars. The primary star is a G7 giant about fifty times more luminous than the sun. It has an effective temperature of 5,100 K and a radius of 9.2 times greater than the sun. The secondary is an A-type dwarf about 26 times as luminous as the sun.
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HD 183263 is an 8th magnitude subgiant star located approximately 177 light- years away in the constellation Aquila. This star is about to or already ran out of hydrogen fuel at its core and is evolving into a red giant before dying as a white dwarf. It has absolute magnitude (apparent magnitude at 10 pc) of 4.16 compared to the Sun’s 4.83, which indicates the star is more luminous than our Sun, and therefore hotter by about 100 K.
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Delta Corvi has more than 2.7 times the mass of the Sun, which is causing it to radiate a much higher energy output—roughly 69 times the Sun's luminosity. The effective temperature of the outer atmosphere is , giving it the white hue of an A-type star. The spectrum matches a stellar classification of . However it is more luminous—65-70 times that of the Sun—than it would be if it were on the main sequence.
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NGC 2 is a spiral galaxy in the constellation Pegasus, discovered by Lawrence Parsons, 4th Earl of Rosse on 20 August 1873, and was described as "very faint, small, south of NGC 1." It lies slightly to the south of NGC 1. It is a faint spiral galaxy of apparent magnitude 14.2. NGC 2 is about 115,000 light years in diameter, but is 3 to 5 more luminous than the Milky Way as it is quite compact.
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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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Eta Carinae observed in different wavelengths Eta Carinae is a highly luminous hypergiant star. Estimates of its mass range from 100 to 150 times the mass of the Sun, and its luminosity is about four million times that of the Sun. This object is currently the most massive star that can be studied in great detail, because of its location and size. Several other known stars may be more luminous and more massive, but data on them is far less robust.
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The period has changed at times by as much as 16 minutes from its average of around 9 days and 2 hours. The star also is considered peculiar compared to other W Virginis stars such as W Virginis itself. A sub-group of W Virginis stars in the Large Magellanic Cloud have been discovered to be hotter and more luminous than expected and given a pW (peculiar W Virginis) classification. It is proposed that κ Pav should also be given a pW classification.
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HD 73534 is an 8th magnitude G-type subgiant star located approximately 272 light years away in the constellation Cancer. A G5 star, it has evolved off the main sequence, which is why it is much more luminous than our Sun. In August 2009, it was announced that it has a planet. It is the first planetary system discovered in Cancer since that of 55 Cancri in April 1996, and the sixth planet, as 55 Cancri has five known planets.
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Gliese 408 is a star located 21.6 light years from the Solar System, located in the constellation of Leo. The stars nearest to Gliese 408 are Gliese 402, at 6.26 light years, and AD Leonis, at 6.26 light years. Gliese 408 is a red dwarf with a spectral type of M2.5V. Much dimmer than the Sun, it has a luminosity of only 0.37% compared to the Sun, but still it is much more luminous than other red dwarf stars, like Proxima Centauri.
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HD 16175 is a 7th magnitude G-type star with temperature about 6000 K located approximately 196 light-years away in the Andromeda constellation. This star is only visible through binoculars or better equipment; it is also 3.3 times more luminous, is 1.34 times more massive, and has a radius 1.66 times bigger than our local star. The star HD 16175 is named Buna. The name was selected in the NameExoWorlds campaign by Ethiopia, during the 100th anniversary of the IAU.
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The evolutionary track of star crossing the instability strip during a helium burning blue loop Classical Cepheid variables are 4–20 times more massive than the Sun, and around 1,000 to 50,000 (over 200,000 for the unusual V810 Centauri) times more luminous. Spectroscopically they are bright giants or low luminosity supergiants of spectral class F6 – K2. The temperature and spectral type vary as they pulsate. Their radii are a few tens to a few hundred times that of the sun.
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The two visible components appear as F-type main-sequence stars: the magnitude 5.63 component A has a stellar classification of F0 V, while the cooler, fainter secondary is of class F4 V. Both are themselves are suspected spectroscopic binary stars consisting of roughly equal components. Component B actually has a higher estimated mass than Component A, although the radius of B is smaller. They are both more luminous than the Sun, and have an estimated age of around 500–600 million years.
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This is a giant star with a stellar classification of K4 III. It is 130 times more luminous than the Sun. Kochab has reached a state in its evolution where the outer envelope has expanded to 42 times the radius of the Sun. This enlarged atmosphere is radiating 390 times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 4,030 K. This heat gives the star the orange-hued glow of a K-type star.
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This star has a stellar classification of F2 Ia, with the 'Ia' luminosity class indicating this is a supergiant more luminous than typical supergiants. It has about 12 times the Sun's mass and is radiating about 35,070 times the Sun's luminosity. The radius is uncertain, with estimates ranging from 125 to 400 times that of the Sun. The effective temperature of the outer envelope is about 7,000 K, which gives it a yellow- white hue typical of an F-type star.
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Observations of the open cluster NGC 7419 in 1954 showed that four of its members were luminous red stars, most likely red supergiants. In addition, an unusually red star was found to be variable and probably an even more luminous supergiant. This star was given the variable star designation MY Cephei in 1973 in the 59th name- list of variable stars. MY Cephei is classified as semiregular variable star of sub-type SRc, indicating it is a cool supergiant, although its pulsational period is not known.
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This is a G-type main sequence star with a stellar classification of G1 V. In terms of composition it is similar to the Sun, while the mass and radius are slightly larger. It is 73% more luminous than the Sun and radiates this energy from its outer atmosphere at an effective temperature of . At this heat, the star glows with the yellow hue of a G-type star. It has a low level of surface activity and is a candidate Maunder minimum analog.
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A star whose initial mass is less than approximately will not become a giant star at all. For most of their lifetimes, such stars have their interior thoroughly mixed by convection and so they can continue fusing hydrogen for a time in excess of 1012 years, much longer than the current age of the Universe. They steadily become hotter and more luminous throughout this time. Eventually they do develop a radiative core, subsequently exhausting hydrogen in the core and burning hydrogen in a shell surrounding the core.
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Documents available at Hyman Dreitman Research Centre, Tate Britain Millbank, London SW1P 4RG In the aftermath of the Second World War, Bettina travelled to the Continent. Countries such as Spain or France inspired her works and were subsequently exhibited at The Leicester Galleries and the Hanover Gallery. In 1958 Shaw- Lawrence left England to move to Italy where her oils on canvas became more luminous and serene though her work " might be sets for very sophisticated doll dramas".Reviews and previews:New names this month (May 1963) ARTnews.
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Analysis of Hipparcos photometry shows an amplitude of 0.082 magnitudes and a primary period of 4.76 days. It has not yet been assigned a variable star designation in the General Catalogue of Variable Stars and is still formally listed as a suspected variable. The hydrogen-rich WN stars have been referred to as WNL stars or as WNH stars since they do not necessarily have late nitrogen-sequence spectra. They are systematically more massive and more luminous than stars with similar spectra but lacking nitrogen.
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This bolometric correction is approximately one magnitude for mid B, late K, and early M stars, increasing to three magnitudes (a factor of 15) for O and mid M stars. All supergiants are larger and more luminous than main sequence stars of the same temperature. This means that hot supergiants lie on a relatively narrow band above bright main sequence stars. A B0 main sequence star has an absolute magnitude of about −5, meaning that all B0 supergiants are significantly brighter than absolute magnitude −5\.
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The first stars in the universe are thought to have been considerably brighter and more massive than the stars in the modern universe. Part of the theorized population III of stars, their existence is necessary to explain observations of elements other than hydrogen and helium in quasars. Possibly larger and more luminous than any supergiant known today, their structure was quite different, with reduced convection and less mass loss. Their very short lives are likely to have ended in violent photodisintegration or pair instability supernovae.
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Classical Cepheids are 4–20 times more massive than the Sun and up to 100,000 times more luminous. These Cepheids are yellow bright giants and supergiants of spectral class F6 – K2 and their radii change by of the order of 10% during a pulsation cycle. Leavitt's work on Cepheids in the Magellanic Clouds led her to discover the relation between the luminosity and the period of Cepheid variables. Her discovery provided astronomers with the first "standard candle" with which to measure the distance to faraway galaxies.
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According to this study, the brighter star is the more luminous, its luminosity 200,000 times that of the Sun as opposed to the secondary's 63,000 times. However the secondary is the more massive star at 19 Solar masses to the primary's 16. However, a more recent photometric analysis finds several configurations of mass and luminosity ratios that match the observed data. Parallax measurements showed it to be approximately 3000 light years from Earth, but this is unexpectedly close for a star of its spectral type and brightness.
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The brighter star of the Pleione binary pair, component A, is a hot type B star 190 times more luminous than the Sun. It is classified as Be star with certain distinguishing traits: periodic phase changes and a complex circumstellar environment composed of two gaseous disks at different angles to each other. The primary star rotates rapidly, close to its breakup velocity, even faster than Achernar. Although some research on the companion star has been performed, stellar characteristics of the orbiting B component are not well known.
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Hertzsprung–Russell diagram for globular cluster M5. The red-giant branch runs from the thin horizontal subgiant branch to the top right, with a number of the more luminous RGB stars marked in red. The Hertzsprung–Russell diagram (HR diagram) is a plot of stellar luminosity versus surface temperature for a population of stars. During the core hydrogen burning phase of a Sun-like star's lifetime, it will appear on the HR diagram at a position along a diagonal band called the main sequence.
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It is also one of the most luminous quasars known, with an absolute magnitude of −26.7, meaning that if it were only as distant as Pollux (~10 parsecs) it would appear nearly as bright in the sky as the Sun. Since the sun's absolute magnitude is 4.83, it means that the quasar is over 4 trillion times more luminous than the Sun at visible wavelengths. The mass of its central black hole has been measured to be 886 ± 187 million solar masses through broad emission-line reverberation mapping.
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HD 17156, named Nushagak by the IAU, is a yellow subgiant star approximately 255 light-years away in the constellation of Cassiopeia. The apparent magnitude is 8.17, which means it is not visible to the naked eye but can be seen with good binoculars. A search for a binary companion star using adaptive optics at the MMT Observatory was negative. The star is more massive and larger than our Sun while Its absolute magnitude of 3.70 and spectral type of G0, show that it is both hotter and more luminous.
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If it were at the centre of the Solar System, it would extend 90% of the way to the orbit of Mercury. The radius and temperature relative to the Sun means that it is 10,700 times more luminous than the Sun, and its position in the H-R diagram relative to theoretical evolutionary tracks means that it is times as massive as the Sun. Measurements of its shape find a 1.1° departure from spherical symmetry. Canopus is a source of X-rays, which are probably produced by its corona, magnetically heated to several million Kelvin.
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An architectural firm had been retained in 2010 to implement the project designed to make the hallway a better "window" to Brussels for the many travellers who begin their journey there. The new tunnel with hops and a more luminous, graffiti resistant environment were completed in 2013. Although Brussels' Central Station is at the very heart of the city, its capacity is not adapted to present usage levels ( 70,000 passengers on a weekday), let alone future levels. The interior and the platforms have been renovated in recent years, but the main problem (i.e.
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The explosion was at least 100 times more luminous than any previously observed supernova, with the progenitor star being estimated 150 times more massive than the Sun. Although this had some characteristics of a Type Ia supernova, Hydrogen was found in the spectrum. It is thought that SN 2006gy is a likely candidate for a pair-instability supernova. SN 2005ap, which was discovered by Robert Quimby who also discovered SN 2006gy, was about twice as bright as SN 2006gy and about 300 times as bright as a normal type II supernova.
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These stars also become hotter during core helium fusion, but they have different core masses and hence different luminosities from HB stars. They vary in temperature during core helium fusion and perform a blue loop before moving to the asymptotic giant branch. Stars more massive than about also ignite their core helium smoothly, and also go on to burn heavier elements as a red supergiant. Stars remain on the horizontal branch for around 100 million years, becoming slowly more luminous in the same way that main sequence stars increase luminosity as the virial theorem shows.
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When adapted for bright conditions (photopic vision), the eye is most sensitive to light at a wavelength of 555 nm. Light with a given amount of radiant energy will have more luminous energy if the wavelength is 555 nm than if the wavelength is longer or shorter. Light whose wavelength is well outside the visible spectrum has a luminous energy of zero, regardless of the amount of radiant energy present. The SI unit of luminous energy is the lumen second, which is unofficially known as the talbot in honor of William Henry Fox Talbot.
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This is an F-type main-sequence star with a spectral type of F9V Fe+0.4, indicating it is similar to the Sun but somewhat hotter and more luminous. The notation 'Fe+0.4' indicates strong iron absorption lines; the star is indeed metal-rich, with an iron abundance 45% greater than the Sun's. Nu Phoenicis has an estimated mass of 1.17 times the solar mass and a radius of 1.26 times the solar radius. It is shining with about double the solar luminosity at an effective temperature of 6,070 K.
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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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Pismis 24-1 has been resolved visually into two components, usually labelled as NE and SW from their orientation with each other. Pismis 24-1NE is slightly more luminous and hotter than 24-1SW, but is known to be a spectroscopic binary. This is surprising given the spectral luminosity classes, because it would make the individual supergiant stars less luminous than a single cooler giant star. It could be that the interaction between the components of 24-1NE is confusing its classification, or the O4 giant may also be a close binary.
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Prominent stars in the neighborhood of the Sun (center) This list of nearest bright stars is a table of stars found within 15 parsecs (48.9 light-years) of the Sun that have an absolute magnitude of +8.5 or brighter, which is approximately comparable to a listing of stars more luminous than a red dwarf. Right ascension and declination coordinates are for the epoch J2000. The distance measurements are based on the Hipparcos Catalogue and other astrometric data. In the event of a spectroscopic binary, the combined spectral type and absolute magnitude are listed in italics.
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Based on its redshift and location projected on the nucleus of a large galaxy, the distance of ASASSN-15lh is calculated at 1,171 Mpc, in a large luminous galaxy. At its peak, the absolute magnitude of ASASSN-15lh in the AB magnitude system u band was −23.5. Its bolometric luminosity is twice that of the previous brightest type-I superluminous supernova, iPTF13ajg. At its brightest, it was approximately 50 times more luminous than the whole Milky Way galaxy, with an energy flux 570 billion times greater than the Sun.
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Gliese 877 (GJ 877 / HIP 113229 / LHS 531)LHS 531 -- High proper-motion Star (SIMBAD) is a red dwarf located in the southern constellation of Octans, near the boundary with Indus. Gliese 877's bolometric luminosity is just 2.3% of our sun's. It shines with an apparent magnitude of +10.22, so it cannot be seen with the naked eye. Nevertheless, it is considerably brighter than other red dwarfs, such as Proxima Centauri, the closest red dwarf to our Solar System; in particular, it is almost 14 times more luminous than Proxima.
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The primary component, 17 Lyrae A, is a 5th magnitude main sequence star of the spectral type F0, meaning it has a surface temperature of about 6,750 K. It is about 60% more massive than the sun and 16 times more luminous. It has been catalogued as an Am star but is now believed to be a relatively normal quickly-rotating star. The visible companion 17 Lyrae B is a 9th magnitude star of an unknown spectral type. The spectroscopic companion cannot be detected in the spectrum and its properties are uncertain.
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The terms giant and dwarf were coined for stars of quite different luminosity despite similar temperature or spectral type by Ejnar Hertzsprung about 1905. Giant stars have radii up to a few hundred times the Sun and luminosities between 10 and a few thousand times that of the Sun. Stars still more luminous than giants are referred to as supergiants and hypergiants. A hot, luminous main-sequence star may also be referred to as a giant, but any main-sequence star is properly called a dwarf no matter how large and luminous it is.
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As with the earlier collapse of the helium core, this starts convection in the outer layers, triggers a second dredge-up, and causes a dramatic increase in size and luminosity. This is the asymptotic giant branch (AGB) analogous to the red-giant branch but more luminous, with a hydrogen-burning shell contributing most of the energy. Stars only remain on the AGB for around a million years, becoming increasingly unstable until they exhaust their fuel, go through a planetary nebula phase, and then become a carbon–oxygen white dwarf., § 7.1–7.4.
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The star itself is a hot supergiant thought to be seventy times more massive than the sun and over a million times more luminous. It has evolved away from the main sequence (being an O-class star, when it was in MS) and is so luminous and large that it is losing material through its stellar wind over a billion times faster than the sun. It would lose more material than the sun contains in about 25,000 years. It is expected to evolve into Wolf-Rayet star in several hundreds thousand years.
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The painting's color palette is also typical of the Futurist palette. Balla chose ultra bright colors, a hallmark of the style which Boccioni explains in "Futurist Painting: Technical Manifesto": > Your eyes, accustomed to semi-darkness, will soon open to more radiant > visions of light. The shadows which we shall paint shall be more luminous > than the highlights of our predecessors, and our pictures, next to those of > the museums, will shine like blinding daylight compared with deepest night. Not only do the pigments nearly shine, they do not mix with each other.
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Mintaka is 915 light years away and shines with magnitude 2.21. It is 90,000 times more luminous than the Sun and is a double star: the two orbit each other every 5.73 days. In the Northern Hemisphere, Orion's Belt is best visible in the night sky during the month of January around 9:00 pm, when it is approximately around the local meridian. Just southwest of Alnitak lies Sigma Orionis, a multiple star system composed of five stars that have a combined apparent magnitude of 3.7 and lying 1150 light years distant.
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Cygnus OB2 #12 is an extremely bright blue hypergiant with an absolute bolometric magnitude (all electromagnetic radiation) of −10.9, among the most luminous stars known in the galaxy. This makes the star nearly two million times more luminous than the Sun, although less than half the estimates when the star was first discovered. It is now known to be a binary, with the companion approximately a tenth as bright. A very approximate initial estimate of the orbit gives the total system mass as and the period as 30 years.
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In practice, though, this has not proved to be as much of a problem as was feared. Rather, with the increased use of automated long-play systems in cinemas, the greater strength of polyester has been a significant advantage in lessening the risk of a film performance being interrupted by a film break. Despite its self-oxidizing hazards, nitrate is still regarded highly as the stock is more transparent than replacement stocks, and older films used denser silver in the emulsion. The combination results in a notably more luminous image with a high contrast ratio.
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They cannot fuse carbon and heavier elements after the helium is exhausted, so they eventually just lose their outer layers, leaving the core of a white dwarf. The phase where these stars have both hydrogen and helium burning shells is referred to as the asymptotic giant branch (AGB), as stars gradually become more and more luminous class M stars. Stars of may fuse sufficient carbon on the AGB to produce an oxygen- neon core and an electron-capture supernova, but astrophysicists categorise these as super-AGB stars rather than supergiants.
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Eta Leonis is a white supergiant with the stellar classification A0Ib. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. Though its apparent magnitude is 3.5, making it a relatively dim star to the naked eye, it is nearly 20,000 times more luminous than the Sun, with an absolute magnitude of -5.60. The Hipparcos astrometric data has estimated the distance of Eta Leonis to be roughly 390 parsecs from Earth, or 1,270 light years away.
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Nor would an extreme velocity help to explain 3C 273's huge radio emissions. If the redshift was cosmological (now known to be correct), the large distance implied that 3C 273 was far more luminous than any galaxy, but much more compact. Also, 3C 273 was bright enough to detect on archival photographs dating back to the 1900s; it was found to be variable on yearly timescales, implying that a substantial fraction of the light was emitted from a region less than 1 light-year in size, tiny compared to a galaxy.
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Based upon the features of its spectrum, Beta Librae has a stellar classification of B8 V, making it a B-type main sequence star. It is about 130 times more luminous than the Sun and has a surface temperature of , double that of the Sun. This high temperature produces light with a simple spectrum, making it ideal for examining the interstellar gas and dust between Earth and the star. Like many stars of its kind, it is spinning rapidly, over 100 times faster than the Sun with a projected rotational velocity of .
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Eta Carinae A is classified as a luminous blue variable (LBV) due to the distinctive spectral and brightness variations. This type of variable star is characterised by irregular changes from a high temperature quiescent state to a low temperature outburst state at roughly constant luminosity. LBVs in the quiescent state lie on a narrow instability strip, with more luminous stars being hotter. In outburst all LBVs have about the same temperature, which is near 8,000 K. LBVs in a normal outburst are visually brighter than when quiescent although the bolometric luminosity is unchanged.
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In the latter case it would have had a luminosity around (being 0.43 times as luminous as its companion), and in the former case it would have been more luminous (about 1.9 times as luminous as its companion). The star may have originally had a radius roughly and its temperature would have been that of a B-type star (more than 10,000K but less than 30,000K). Munari et al. (2005) suggested that the progenitor star was a very massive supergiant with an initial mass of about , but this has been contested.
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Hubble's field of view. The lower image quadrant represents a zoomed in view. SCP 06F6 is (or was) an astronomical object of unknown type, discovered on February 21, 2006, in the constellation Boötes during a survey of galaxy cluster CL 1432.5+3332.8 with the Hubble Space Telescope's Advanced Camera for Surveys Wide Field Channel. The European X-ray satellite XMM Newton made an observation in early August 2006 which appears to show an X-ray glow around SCP 06F6, two orders of magnitude more luminous than that of supernovae.
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For example, the shadow of a red apple will appear to contain a little blue-green. This effect is often copied by painters who want to create more luminous and realistic shadows. Also, if you stare at a square of color for a long period of time (thirty seconds to a minute), and then look at a white paper or wall, you will briefly see an afterimage of the square in its complementary color. Placed side-by-side as tiny dots, in partitive color mixing, complementary colors appear gray.
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Changes in the visual magnitude, temperature, radius, and bolometric luminosity as χ Cygni pulsates χ Cygni is much larger and cooler than the sun, so large that it is thousands of times more luminous despite the low temperature. It pulsates, with both the radius and temperature varying over approximately 409 days. The temperature varies from about 2,400 K to about 2,700 K and the radius varies from about to . These pulsations cause the luminosity of the star to vary from about to , but they cause the visual brightness to vary by over 10 magnitudes.
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Mira, a variable asymptotic giant branch red giant A red giant is a star that has exhausted the supply of hydrogen in its core and has begun thermonuclear fusion of hydrogen in a shell surrounding the core. They have radii tens to hundreds of times larger than that of the Sun. However, their outer envelope is lower in temperature, giving them a reddish-orange hue. Despite the lower energy density of their envelope, red giants are many times more luminous than the Sun because of their great size.
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These parameters make Westerlund 1-26 one of most luminous red supergiants and are also similar to those estimated for another notable red supergiant star, VY Canis Majoris. An earlier calculation of the luminosity and the temperature by fitting the spectral energy distribution and based on the spectrum by using DUSTY model gave a far much higher luminosity of just around and a photospheric temperature of , which all correspond to a very large radius of and is considerably more luminous than expected for any red supergiant and extreme.
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Upsilon Andromedae A is a yellow-white dwarf of spectral type F8V, similar to the Sun, but younger, more massive, and more luminous. According to its entry in the Geneva–Copenhagen survey, the star is around 3.1 billion years old and has a similar proportion of iron relative to hydrogen to the Sun. At around 1.3 solar masses, it will have a shorter lifetime than the Sun. The amount of ultraviolet radiation received by any planets in the star's habitable zone would be similar to the ultraviolet flux the Earth receives from the Sun.
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A small number of Am stars show unusually late spectral types and particularly strong luminosity effects. Although Am stars in general show abnormal luminosity effects, stars such as ρ Puppis are believed to be more evolved and more luminous than most Am stars, lying above the main sequence. Am stars and δ Scuti variables lie in approximately the same location on the H–R diagram, but it is rare for a star to be both an Am star and a δ Scuti variable. ρ Puppis is one example and δ Delphini is another.
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All three (four, including HD 150135) of the brightest stars are massive luminous O class main sequence stars, 33-63 times as massive as the sun. They are around 10 times the size of the sun, but 6-8 times hotter and each is over 100,000 times as luminous. The primary star is the closest O3 star to Earth, 46,500 K, visually 18,000 times as bright as the sun, but because of its high temperature it is around three quarters of a million times more luminous including all wavelengths.
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Light curve of Delta Cephei, a yellow supergiant classical Cepheid variable Many yellow supergiants are in a region of the HR diagram known as the instability strip because their temperatures and luminosities cause them to be dynamically unstable. Most yellow supergiants observed in the instability strip are Cepheid variables, named for δ Cephei, which pulsate with well-defined periods that are related to their luminosities. This means they can be used as standard candles for determining the distance of stars knowing only their period of variability. Cepheids with longer periods are cooler and more luminous.
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NGC 604 is an H II region inside the Triangulum Galaxy. It was discovered by William Herschel on September 11, 1784. It is among the largest H II regions in the Local Group of galaxies; at the galaxy's estimated distance of 2.7 million light-years, its longest diameter is roughly 1,520 light years (~460 parsecs) (14.38031 exameters), over 40 times the size of the visible portion of the Orion Nebula. It is over 6,300 times more luminous than the Orion Nebula, and if it were at the same distance it would outshine Venus.
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38 Lyncis was given as a standard star for the spectral class of A3 V when the Morgan-Keenan classification system was first defined in 1943, apparently for the two components combined. The primary star, component A, is a class A main sequence star around twice the mass of the sun. An effective temperature of and a radius of mean that it is over thirty times more luminous than the sun. It has been listed as a λ Boötis star, although it is no longer considered to be a member.
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Studies in the late 20th century began to show that all giants of class M were variable with amplitudes of 10 milli-magnitudes of more, and that late K class giants were also likely to be variable with smaller amplitudes. Such variable stars were amongst the more luminous red giants, close to the tip of the RGB, but it was difficult to argue that they were all actually AGB stars. The stars showed a period amplitude relationship with larger amplitude variables pulsating more slowly. Microlensing surveys in the 21st century have provided extremely accurate photometry of thousands of stars over many years.
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It is a main sequence star with a stellar classification of B6 Vep, but is about 3,150 times more luminous than the Sun. Infrared observations of the star using an adaptive optics system on the Very Large Telescope show that it has a companion star in a close orbit. This appears to be an A-type star in the stellar classification range A0V–A3V, which suggests a stellar mass of about double that of the Sun. The separation of the two stars is roughly 12.3 AU and their orbital period is at least 14–15 years.
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The group exhibits a relatively small harmonic mean radius (230 ± 40 kpc) due to the concentration at its core of more luminous galaxies. All together, the group has an overall luminosity of 7.8 ± 1.6 L⊙. The Dorado Group contains three dominant smaller groups within itself, NGC 1672 Group, NGC 1566 Group and the NGC 1433 Group, as evidenced by the H I distribution of the region. The Dorado Group is in the Fornax Wall that connects these three groups. Due to its location in the Fornax Wall, the group is at a similar distance as the Fornax Cluster.
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Luminous blue variables like P Cygni are very rare and short lived, and only form in regions of galaxies where intense star formation is happening. LBV stars are so massive and energetic (typically 50 times the mass of the Sun and tens of thousands of times more luminous) that they exhaust their nuclear fuel very quickly. After shining for only a few million years (compared to several billion years for the Sun) they erupt in a supernova. The recent supernova SN 2006gy was likely the end of an LBV star similar to P Cygni but located in a distant galaxy.
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The most luminous stars are always young stars, no more than a few million years for the most extreme. In the Hertzsprung–Russell diagram, the x-axis represents temperature or spectral type while the y-axis represents luminosity or magnitude. The vast majority of stars are found along the main sequence with blue Class O stars found at the top left of the chart while red Class M stars fall to the bottom right. Certain stars like Deneb and Betelgeuse are found above and to the right of the main sequence, more luminous or cooler than their equivalents on the main sequence.
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H–R diagram of the entire Hipparcos catalog A Hertzsprung–Russell (H–R) diagram is a scatter plot of stars with temperature or spectral type on the x-axis and absolute magnitude or luminosity on the y-axis. H–R diagrams of all stars, show a clear diagonal main sequence band containing the majority of stars, a significant number of red giants (and white dwarfs if sufficiently faint stars are observed), with relatively few stars in other parts of the diagram. Subgiants occupy a region above (i.e. more luminous than) the main sequence stars and below the giant stars.
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H-R diagram illustrating the location of Type II Cepheids in the instability strip Type II Cepheids are variable stars which pulsate with periods typically between 1 and 50 days. They are population II stars: old, typically metal- poor, low mass objects. Like all Cepheid variables, Type IIs exhibit a relationship between the star's luminosity and pulsation period, making them useful as standard candles for establishing distances where little other data is available Longer period Type II Cepheids, which are more luminous, have been detected beyond the Local Group in the galaxies NGC 5128 and NGC 4258.
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The Wolf–Rayet star that produces the characteristic emission line spectrum of WR 104 has a resolved companion and an unresolved spectroscopic companion, forming a triple system. The spectroscopic pair consists of the Wolf–Rayet star and a B0.5 main sequence star. The WR star is visually 0.3 magnitudes fainter than the main sequence star, although the WR star is typically considered the primary, as it dominates the appearance of the spectrum and is more luminous. The two are in a nearly circular orbit separated by about 2 AU, which would be about one milli-arcsecond at the assumed distance.
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Capella Aa is the cooler and more luminous of the two with spectral class K0III; it is 78.7 ± 4.2 times the Sun's luminosity and 11.98 ± 0.57 times its radius. An aging red clump star, it is fusing helium to carbon and oxygen in its core. Capella Ab is slightly smaller and hotter and of spectral class G1III; it is 72.7 ± 3.6 times as luminous as the Sun and 8.83 ± 0.33 times its radius. It is in the Hertzsprung gap, corresponding to a brief subgiant evolutionary phase as it expands and cools to become a red giant.
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The neutral atomic hydrogen distribution in NGC 7013 is mostly located in the two rings. In between the two rings there is a very low concentration of interstellar medium. The low level of neutral atomic hydrogen in the disk of NGC 7013 and the reddish color of the galaxy suggests that the gas content of the galactic disc has fallen below the threshold at which star formation is likely to take place. The small bulge-to-disk ratio and the slow rotation velocity show that NGC 7013 is a low-mass, low-density galaxy unlike the more luminous, typical lenticular galaxies.
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This is an evolving G-type subgiant star with a stellar classification of G6 IV and is not considered active, having a chromospheric activity index of −5.04. It has about the same mass as the Sun but is 25% more luminous. The photosphere is radiating energy at an effective temperature of 5,614 K. It has a higher than solar metallicity rating – a term astronomers use to describe the abundance of elements other than hydrogen and helium. The discovery of a planetary system orbiting HD 134606 was announced in 2011 following an eight-year survey carried out at the La Silla Observatory in Chile.
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Alpha Centauri A, also known as Rigil Kentaurus, is the principal member, or primary, of the binary system. It is a solar-like main-sequence star with a similar yellowish colour, whose stellar classification is spectral type G2 V; it is slightly larger and more luminous than the Sun. Alpha Centauri A is about 10 percent more massive than the Sun, with a radius about 22 percent larger. When considered among the individual brightest stars in the sky (excluding the Sun), it is the fourth brightest at an apparent magnitude of −0.01, being slightly fainter than Arcturus at an apparent magnitude of −0.05.
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The exact spectral class of the star is not yet known. Different estimations gives a range F8-K5Vea, meaning that there is agreement in identifying it as a main sequence star more luminous and with stronger emission lines than the usual, a typical classification for young stars that are near the main sequence phase. The color indexes vary with the star's brightness, but the spectral class of BM Andromedae does not change with the decrease of luminosity. Strong H-alpha lines in the spectra are a sign of a gaseous envelope, while an infrared excess indicates the existence of an extended dust envelope.
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Since then automated searches have confirmed another four, including one of magnitude 5.9 at maximum. There are also several candidates that have not yet been observed to fade, and several DY Per stars in the Large Magellanic Cloud. Although DY Persei variables have been considered a subset of the R CrB variables because of their irregular fades and carbon-rich spectra, they may simply be an unusual type of carbon star unrelated to the more massive and more luminous R CrB variables. The fades may be caused by obscuring ejection events rather than carbon condensation in the atmospheres of the stars.
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Another model based on visual brightness gives an unexpectedly large luminosity of , with the difference due mainly to the assumptions about the level of extinction. The radius corresponding to the higher luminosity would be . These parameters are larger and more luminous than expected for any red supergiant, making them doubtful. More recently, integration of the spectral energy distributions across a full range of wavelengths from U band to the 60 micron microwave flux gives an even lower luminosity of , and calculation of the bolometric luminosity based on its Gaia Data Release 2 parallax gives a luminosity below with a corresponding radius of .
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Two distinct types of Cepheid variable have been identified, which have different period-luminosity relationships: Classical Cepheid variables are young massive population I stars; type II Cepheids are older population II stars with low masses, including W Virginis variables, BL Herculis variables and RV Tauri variables. The Classical Cepheids are more luminous than the type II Cepheids with the same period. R Coronae Borealis variables are often yellow supergiants, but their variability is produced by a different mechanism from the Cepheids. At irregular intervals, they become obscured by dust condensation around the star and their brightness drops dramatically.
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No star closer than Canopus is more luminous than it, and it has been the brightest star in Earth's night sky during three epochs over the past four million years. Other stars appear brighter only during relatively temporary periods, during which they are passing the Solar System much closer than Canopus. About 90,000 years ago, Sirius moved close enough that it became brighter than Canopus, and that will remain so for another 210,000 years. But in 480,000 years, as Sirius moves further away and appears fainter, Canopus will once again be the brightest, and will remain so for a period of about 510,000 years.
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This is the horizontal branch (for population II stars) or red clump (for population I stars), or a blue loop for stars more massive than about . After the completion of helium burning in the core, the star again moves to the right and upwards on the diagram, cooling and expanding as its luminosity increases. Its path is almost aligned with its previous red-giant track, hence the name asymptotic giant branch, although the star will become more luminous on the AGB than it did at the tip of the red giant branch. Stars at this stage of stellar evolution are known as AGB stars.
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Some ultra diffuse galaxies found in the Coma Cluster, about 330 million light years from Earth, have diameters of with 1% of the stars of the Milky Way Galaxy. The distribution of ultra diffuse galaxies in the Coma Cluster is the same as luminous galaxies; this suggests that the cluster environment strips the gas from the galaxies, while allowing them to populate the cluster the same as more luminous galaxies. The similar distribution in the higher tidal force zones suggests a larger dark matter fraction to hold the galaxies together under the higher stress. Dragonfly 44, an ultra diffuse galaxy in the Coma Cluster, is one example.
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This is considerably more luminous than expected for any red supergiant and extreme even for a yellow hypergiant. The effective temperature derived from matching infrared spectra is 5,000 K, while the temperature calculated from a radius of and luminosity of is 4,290 ± 760 K. The close secondary HR 5171 Ab is a luminous yellow star with a radius about a third that of the primary star and an almost identical temperature. From the shape of the eclipse light curve, it is 12% as luminous as the primary and slightly hotter. It is much less massive, estimated at only a tenth of the mass of the primary.
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Absolute magnitudes are denoted by a capital M, with a subscript representing the filter band used for measurement, such as MV for absolute magnitude in the V band. The more luminous an object, the smaller the numerical value of its absolute magnitude. A difference of 5 magnitudes between the absolute magnitudes of two objects corresponds to a ratio of 100 in their luminosities, and a difference of n magnitudes in absolute magnitude corresponds to a luminosity ratio of 100n/5. For example, a star of absolute magnitude MV=3.0 would be 100 times as luminous as a star of absolute magnitude MV=8.0 as measured in the V filter band.
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HV 2112 had historically been treated as a very luminous asymptotic giant branch (AGB) star, a red giant that has exhausted its core helium and is in the last stages of its evolution. Large-amplitude class-M variables and stars with spectral types later than about M5 are almost always AGB stars rather than red supergiants. These stars have a theoretical maximum luminosity and, at the distance of the SMC, HV 2112 was typically calculated to be slightly more luminous than this limit at around . More modern calculations gave higher values for the luminosity of HV 2112 above , which is unambiguously too luminous to be an AGB star.
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An astronomical interferometer is an array of separate telescopes, mirror segments, or radio telescope antennas that work together as a single telescope to provide higher resolution images of astronomical objects such as stars, nebulas and galaxies by means of interferometry. The advantage of this technique is that it can theoretically produce images with the angular resolution of a huge telescope with an aperture equal to the separation between the component telescopes. The main drawback is that it does not collect as much light as the complete instrument's mirror. Thus it is mainly useful for fine resolution of more luminous astronomical objects, such as close binary stars.
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Red light on the back of a bicycle Early bicycle lighting: candle lamps, oil lamps and carbide lamps Early bicycle lamps and two early bottle dynamos (1935) Bicycle lighting is illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination. A secondary purpose is to illuminate reflective materials such as cat's eyes and traffic signs. A third purpose may be to illuminate the roadway so that the rider can see the way ahead. Serving the latter purposes require much more luminous flux and thus more power.
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In our Galaxy, embedded clusters can mostly be found within the Galactic disk or near the Galactic center where most of the star-formation activity is happening. The sizes of stellar objects born in embedded clusters are distributed according to initial mass function, with many low-mass stars formed for every high-mass star. Nevertheless, the high- mass stars of temperature class O and B, which are significantly hotter and more luminous than the low-mass stars, have a disproportionate effect on their interstellar environment by ionizing the gas surrounding them creating H II regions. Many ultra-compact H II regions, the precursors to massive protostars, are associated with embedded clusters.
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In defining the constellation, Lacaille gave twelve stars Bayer designations of Alpha through to Lambda, with two close stars called Eta (one now known by its Henry Draper catalogue number), while Lambda was later dropped due to its dimness. The three brightest stars, Alpha, Beta and Gamma, make up the triangle. Readily identified by its orange hue, Alpha Trianguli Australis is a bright giant star of spectral type K2 IIb-IIIa with an apparent magnitude of +1.91 that is the 42nd-brightest star in the night sky. It lies away and has an absolute magnitude of −3.68 and is 5,500 times more luminous than our Sun.
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Charles Winston was a 19th-century lawyer whose hobby was the study of Medieval glass. In 1847 he published an influential book on its styles and production, including a translation from Theophilus' On Diverse Arts, the foremost Medieval treatise on painting, stained glass and metalwork, written in the early 12th century. Winston's interest in the technicalities of coloured glass production led him to take shards of medieval glass to James Powell and Sons of Whitefriars for analyses and reproduction. Winston observed that windows of medieval glass appeared more luminous than those of early 19th-century production, and set his mind to discovering why this was the case.
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Blue loops in these stars can last for around 10 million years, so this type of yellow supergiant is more common than the more luminous types. Stars with masses similar to the sun develop degenerate helium cores after they leave the main sequence and ascend to the tip of the red giant branch where they ignite helium in a flash. They then fuse core helium on the horizontal branch with luminosities too low to be considered supergiants. Stars leaving the blue half of the horizontal branch to be classified in the asymptotic giant branch (AGB) pass through the yellow classifications and will pulsate as BL Herculis variables.
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WASP-15 is a magnitude 11 star located about 1000 light-years away in the constellation Centaurus. The star, which is more massive, larger, hotter, and more luminous than the Sun, is also less metal-rich than the Sun. WASP-15 has one known planet in its orbit, WASP-15b; the planet is a Hot Jupiter with an anomalously high radius, a phenomenon which may be explained by the presence of an internal heat source. The star was first observed by the SuperWASP program in 2006; future measurements in 2007 and 2008, as well as follow-up observations and analysis, eventually led to the discovery of WASP-15b using the transit method and Doppler spectroscopy.
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Norman is now an associate scientist and the Deputy Director of the Community Science and Data Center (CSDC) at the National Optical-Infrared Astronomy Research Laboratory (NOIRLab), which operates NOAO as of October 1, 2019. Her research interests have evolved to focus on Active Galactic Nuclei (AGN), which are compact regions at the center of galaxies that are thought to be powered by supermassive black holes. AGN, which can be more luminous than an entire galaxy of stars, form as stars and gases are accreted through the activity of a supermassive black hole. Norman's research seeks to understand how these active galaxies form and why some of them are brighter than others.
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Diagram of Rho Geminorum and the four companions listed in the WDS The positions of the three stars in the Rho Geminorum system on the Hertzsprung-Russell diagram. As Rho Geminorum B does not have a known B-V or temperature, a line through its absolute magnitude is drawn instead. Rho Geminorum A is a bright star with a spectral type F0V, meaning that it is a main sequence that is over a thousand kelvins hotter, one-third more massive, two-thirds larger and five-and-a-half times more luminous than the Sun. With an apparent magnitude of 4.25, it is approximately the seventeenth- brightest star in the constellation of Gemini.
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Two letters of his also remain, his profession of faith, and a short elegy on contempt for the world which shows that he cultivated poetry. St Bruno's Commentaries reveal that he knew a little Hebrew and Greek; he was familiar with the Church Fathers, especially Augustine of Hippo and Ambrose. "His style," said Dom Rivet, "is concise, clear, nervous and simple, and his Latin as good as could be expected of that century: it would be difficult to find a composition of this kind at once more solid and more luminous, more concise and more clear." In Catholic art, Saint Bruno can be recognized by a skull that he holds and contemplates, with a book and a cross.
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The outburst of dwarf novae are thought to arise from a thermal instability of the disk, that increases mass flow and temperature and hence the luminosity increases. In DX Andromedae different outbursts don't reach the same peak luminosity and don't occur at a regular rate, but they retain the same shape in the decaying part. It seems that the peak luminosity is correlated to the length of the preceding cycle, and the more luminous is the outburst, the faster the luminosity peak is reached. These trends can be explained by matter accumulating in the disk; more matter is accumulated in the disk during a longer cycle, and it can power a stronger outburst.
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A blue dwarf is a predicted class of star that develops from a red dwarf after it has exhausted much of its hydrogen fuel supply. Because red dwarfs fuse their hydrogen slowly and are fully convective (allowing their entire hydrogen supply to be fused, instead of merely that in the core), the Universe is currently not old enough for any blue dwarfs to have formed yet, but their future existence is predicted based on theoretical models. Stars increase in luminosity as they age, and a more luminous star needs to radiate energy more quickly to maintain equilibrium. Stars larger than red dwarfs do this by increasing their size and becoming red giants with larger surface areas.
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Its most luminous members are and , with both having luminosities several million times that of the Sun, and there are three other extreme stars with O3 spectral classes. Both and are binaries, with the primary stars contributing most of the luminosity, but with companions which are themselves more massive and luminous than most stars. Totalling all wavelengths, is estimated to be the more luminous of the two, 6,300,000 times the Sun's luminosity (absolute bolometric magnitude -12.25) compared to at 5,000,000 times the Sun's luminosity (absolute bolometric magnitude -12.0). However, appears by far the brightest object, both because it is brighter in visual wavelengths and because it is embedded in nebulosity which exaggerates the luminosity.
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They call luminous that which strikes the imagination, > and dark that which the imagination has to penetrate. > > We do not mechanically connect the sensation of white with the idea of > light, any more than we connect the sensation of black with the idea of > darkness. We know that a precious stone in black, and in a mat black, can be > more luminous than the white satin or the pink of its jewel case. Loving > light, we refuse to measure it, and we avoid the geometrical ideas of the > focus and the ray, which imply the repetition-contrary to the principle of > variety which guides us-of bright planes and sombre intervals in a given > direction.
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Wolf–Rayet stars are also high-mass luminous evolved stars, hotter than most supergiants and smaller, visually less bright but often more luminous because of their high temperatures. They have spectra dominated by helium and other heavier elements, usually showing little or no hydrogen, which is a clue to their nature as stars even more evolved than supergiants. Just as the AGB stars occur in almost the same region of the HR diagram as red supergiants, Wolf–Rayet stars can occur in the same region of the HR diagram as the hottest blue supergiants and main-sequence stars. The most massive and luminous main- sequence stars are almost indistinguishable from the supergiants they quickly evolve into.
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LBVs observed only at a particular time or over a period of time when they are stable, may simply be designated as hot supergiants or as candidate LBVs due to their luminosity. Hypergiants are frequently treated as a different category of star from supergiants, although in all important respects they are just a more luminous category of supergiant. They are evolved, expanded, massive and luminous stars like supergiants, but at the most massive and luminous extreme, and with particular additional properties of undergoing high mass-loss due to their extreme luminosities and instability. Generally only the more evolved supergiants show hypergiant properties, since their instability increases after high mass-loss and some increase in luminosity.
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A super star cluster (SSC) is a very massive young open cluster that is thought to be the precursor of a globular cluster. These clusters are referred to as "super" due to the fact that they are relatively more luminous and contain more mass than other young star clusters. The SSC, however, does not have to physically be larger than other clusters of lower mass and luminosity. They typically contain a very large number of young, massive stars that ionize a surrounding HII region or a so-called "Ultra dense HII regions (UDHIIs)" in the Milky Way Galaxy as well as in other galaxies (however, SSCs do not always have to be inside an HII region).
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It is classified as a Delta Scuti type variable star and its brightness varies from magnitude +6.06 to +6.15 with periods of around 70 to 80 minutes. These Delta Scuti variables are a class of short-period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. Observations over the decades have shown that its colour slightly changes and it exhibits variation in light that indicate the star is actually an ellipsoidal binary with a period of seven days. The system is more luminous than expected, given the spectrum and distance of the primary star, indicating that the companion star must be contributing a good proportion of its light.
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In 1965, twelve years after the first maser was built in a laboratory, a hydroxyl (OH) maser was discovered in the plane of the Milky Way.Weaver et al. (1965) Masers of other molecules were discovered in the Milky Way in the following years, including water (H2O), silicon monoxide (SiO), and methanol (CH3OH).Reid and Moran (1981) The typical isotropic luminosity for these galactic masers is .Moran (1976) The first evidence for extragalactic masing was detection of the hydroxyl molecule in NGC 253 in 1973, and was roughly ten times more luminous than galactic masers.Elitzur (1992), p. 308. In 1982, the first megamaser was discovered in the ultraluminous infrared galaxy Arp 220.Baan, Wood, and Haschick (1982) The luminosity of the source, assuming it emits isotropically, is roughly .
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Intrinsic variable types in the Hertzsprung–Russell diagram showing the Yellow Hypergiants above (i.e. more luminous than) the Cepheid instability strip A yellow hypergiant (YHG) is a massive star with an extended atmosphere, a spectral class from A to K, and, starting with an initial mass of about 20–60 solar masses, has lost as much as half that mass. They are amongst the most visually luminous stars, with absolute magnitude (MV) around −9, but also one of the rarest with just 15 known in the Milky Way and six of those in just a single cluster. They are sometimes referred to as cool hypergiants in comparison with O- and B-type stars, and sometimes as warm hypergiants in comparison with red supergiants.
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Iota Herculis is a B-type subgiant star that is at the end of its hydrogen fusion stage. With a stellar classification B3IV, it is considerably larger than the Sun, having a mass that is 6.5 times solar and a radius 5.3 times. Though its apparent magnitude is only 3.80, it is 2,500 times more luminous than the Sun, yielding an absolute magnitude of -2.11, brighter in fact than the most of the hot B stars in the Pleiades open star cluster. The Hipparcos satellite mission estimated its distance at roughly 152 parsecs (pc) from Earth, or 496 light years (ly) away; an updated parallax measurement from Floor van Leeuwen in 2007, however, puts the distance at 455ly with a much tighter error factor of only 8ly.
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Venice infused his painting with a gentler edge, a style more acceptable to the local patronage, and one derived from his precursors in Venice, Jan Lys and Domenico Fetti, who had also fused the influence of Caravaggio into Venetian art. Veronese's art inspired him to adopt a bolder and more luminous palette. An example of this style can be found in his Parable of the Wedding Guests (1636, Accademia ligustica di belle arti).Parable of the Wedding Guests at the National Gallery, Australia His style continued at the same time to reveal the strong influence of Rubens as is shown in Allegorical figure (Minerva?) (mid-1630s, Cleveland Museum of Art), which unites the robust forms and brilliant colours of Rubens with the warm atmosphere of Venetian art.
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Hertzsprung–Russell diagram for globular cluster M5, with the horizontal branch marked in yellow, RR Lyrae stars in green, and some of the more luminous red giant branch stars in red The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red giant branch in stars whose masses are similar to the Sun's. Horizontal-branch stars are powered by helium fusion in the core (via the triple-alpha process) and by hydrogen fusion (via the CNO cycle) in a shell surrounding the core. The onset of core helium fusion at the tip of the red giant branch causes substantial changes in stellar structure, resulting in an overall reduction in luminosity, some contraction of the stellar envelope, and the surface reaching higher temperatures.
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A typical spectrum when first formed would be O2If and the star would be mostly or fully convective due to CNO cycle fusion at the very high core temperatures. Sufficiently massive or differentially rotating stars undergo such strong mixing that they remain chemically homogeneous during core hydrogen burning. As core hydrogen burning progresses, a very massive star would slowly expand and become more luminous, becoming a blue hypergiant and eventually an LBV while still fusing hydrogen in the core. When hydrogen at the core is depleted after 2–2.5 million years, hydrogen shell burning continues with further increases in size and luminosity, although hydrogen shell burning in chemically homogeneous stars may be very brief or absent since the entire star would become depleted of hydrogen.
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Evolutionary track for an intermediate mass star similar to χ Cygni χ Cygni is a luminous and variable red giant on the asymptotic giant branch (AGB). This means it has exhausted its core helium, but is not massive enough to start burning heavier elements and is currently fusing hydrogen and helium in concentric shells. Specifically it is on the thermally pulsing portion of the AGB (TP-AGB) which occurs when the helium shell is close to the hydrogen shell and undergoes periodic flashes as it stops fusion for a time and new material accumulates from the hydrogen-burning shell. AGB stars become more luminous, larger, and cooler as they lose mass and the internal shells move closer to the surface.
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Red-giant-branch stars have luminosities up to nearly three thousand times that of the Sun (), spectral types of K or M, have surface temperatures of 3,000–4,000 K, and radii up to about 200 times the Sun (). Stars on the horizontal branch are hotter, with only a small range of luminosities around . Asymptotic-giant- branch stars range from similar luminosities as the brighter stars of the red- giant branch, up to several times more luminous at the end of the thermal pulsing phase. Among the asymptotic-giant-branch stars belong the carbon stars of type C-N and late C-R, produced when carbon and other elements are convected to the surface in what is called a dredge-up.
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The yellow hypergiants are thought to be generally post-red supergiant stars that have already lost most of their atmospheres and hydrogen. A few more stable high mass yellow supergiants with approximately the same luminosity are known and thought to be evolving towards the red supergiant phase, but these are rare as this is expected to be a rapid transition. Because yellow hypergiants are post-red supergiant stars, there is a fairly hard upper limit to their luminosity at around , but blue hypergiants can be much more luminous, sometimes several million . Almost all hypergiants exhibit variations in luminosity over time due to instabilities within their interiors, but these are small except for two distinct instability regions where luminous blue variables (LBVs) and yellow hypergiants are found.
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Mira, the prototype of the Mira variables Mira variables (named for the prototype star Mira) are a class of pulsating stars characterized by very red colours, pulsation periods longer than 100 days, and amplitudes greater than one magnitude in infrared and 2.5 magnitude at visual wavelengths. They are red giants in the very late stages of stellar evolution, on the asymptotic giant branch (AGB), that will expel their outer envelopes as planetary nebulae and become white dwarfs within a few million years. Mira variables are stars massive enough that they have undergone helium fusion in their cores but are less than two solar masses, stars that have already lost about half their initial mass. However, they can be thousands of times more luminous than the Sun due to their very large distended envelopes.
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In some cases, stars may cross the instability strip for a fourth and fifth time when helium shell burning starts. The rate of change of the period of a Cepheid variable, along with chemical abundances detectable in the spectrum, can be used to deduce which crossing a particular star is making. Classical Cepheid variables were B type main sequence stars earlier than about B7, possibly late O stars, before they ran out of hydrogen in their cores. More massive and hotter stars develop into more luminous Cepheids with longer periods, although it is expected that young stars within our own galaxy, at near solar metallicity, will generally lose sufficient mass by the time they first reach the instability strip that they will have periods of 50 days or less.
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The orbit is known extremely accurately and can be used to derive an orbital parallax with far better precision than the one measured directly. The stars are not near enough to each other for the Roche lobe of either star to have been filled and any significant mass transfer to have taken place, even during the red giant stage of the primary star. Modern convention designates the more luminous cooler star as component Aa and its spectral type has been usually measured between G2 and K0. The hotter secondary Ab has been given various spectral types of late (cooler) F or early (warmer) G. The MK spectral types of the two stars have been measured a number of times, and they are both consistently assigned a luminosity class of III indicating a giant star.
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St 2-18 shows the traits and properties of a highly luminous and extreme red supergiant, with a late spectral type of M6, which is unusual for a supergiant star. This places it at the top right corner of the Hertzsprung–Russell diagram. A calculation for finding the bolometric luminosity by fitting the Spectral Energy Distribution (SED) gives the star a luminosity of nearly , with an effective temperature of , which corresponds to a very large radius of , which would be considerably larger and more luminous than theoretical models of the largest, and most luminous red supergiants possible (roughly and respectively). An alternate but older calculation from 2010, still assuming membership of the Stephenson 2 cluster at but based on 12 and fluxes, gives a much lower and relatively modest luminosity of .
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Delta Corvi, traditionally called Algorab, is a double star divisible in small amateur telescopes. The primary is a blue-white star of magnitude 2.9, around 87 light-years from Earth. An enigmatic star around 2.7 times as massive as the Sun, it is more luminous (65–70 times that of the Sun) than its should be for its surface temperature of 10,400 K, and hence is either a 3.2 million year-old very young pre-main sequence star that has not settled down to a stable main sequence life stage, or a 260-million-year-old star that has begun to exhaust its core hydrogen and expand, cool and shine more brightly as it moves away from the main sequence. Its spectral type is given as A0IV, corresponding with the latter scenario.
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Discoveries of many SLSNe in the 21st century showed that not only were they more luminous by an order of magnitude than most supernovae, their remnants were also unlikely to be powered by the typical radioactive decay that is responsible for the observed energies of conventional supernovae. SLSNe events use a separate classification scheme to distinguish them from the conventional type Ia, type Ib/Ic, and type II supernovae, roughly distinguishing between the spectral signature of hydrogen- rich and hydrogen-poor events. Hydrogen-rich SLSNe are classified as Type SLSN-II, with observed radiation passing through the changing opacity of a thick expanding hydrogen envelope. Most hydrogen-poor events are classified as Type SLSN-I, with its visible radiation produced from a large expanding envelope of material powered by an unknown mechanism.
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Light curve of Delta Cephei, the prototype of classical cepheids, showing the regular variations produced by intrinsic stellar pulsations Classical Cepheids (also known as Population I Cepheids, type I Cepheids, or Delta Cepheid variables) undergo pulsations with very regular periods on the order of days to months. Classical Cepheids are Population I variable stars which are 4–20 times more massive than the Sun, and up to 100,000 times more luminous. These Cepheids are yellow bright giants and supergiants of spectral class F6 – K2 and their radii change by (~25% for the longer-period I Carinae) millions of kilometers during a pulsation cycle. Classical Cepheids are used to determine distances to galaxies within the Local Group and beyond, and are a means by which the Hubble constant can be established.
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Once we adjust for the selection effect that hotter, more luminous white dwarfs are easier to observe, we do find that decreasing the temperature range examined results in finding more white dwarfs. This trend stops when we reach extremely cool white dwarfs; few white dwarfs are observed with surface temperatures below 4,000 K, and one of the coolest so far observed, WD 0346+246, has a surface temperature of approximately 3,900 K. The reason for this is that the Universe's age is finite; there has not been enough time for white dwarfs to cool below this temperature. The white dwarf luminosity function can therefore be used to find the time when stars started to form in a region; an estimate for the age of our Galactic disk found in this way is 8 billion years.
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The indication of this type of strong X-ray source means that it is more luminous than any known stellar X-ray source, but less luminous than the X-ray intensity of supermassive black holes, which places it in the range of theorized intermediate black holes. Their exact nature of ULXs has remained a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and a thousands times that of the Sun. A mix of detected natural elements seems to indicate the actual source of the X-ray emissions are debris from the white dwarf. If evidence authenticates the observations from NASA's Chandra X-ray Observatory and the Magellan telescopes, it means the first actual observation of an intermediate black hole.
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This star is slightly smaller and less massive than the Sun, making it marginally dimmer than the Sun in terms of luminosity; it is about a third more luminous than Tau Ceti or Alpha Centauri B. The projected equatorial rotation rate (v sin i) is 4.0 km/s, compared to 2 km/s for the Sun. 82 G. Eridani is a high-velocity star—it is moving quickly compared to the average—and hence is probably a member of Population II, generally older stars whose motions take them well outside the plane of the Milky Way. Like many other Population II stars, 82 G. Eridani is somewhat metal-deficient (though much less deficient than many), and is older than the Sun. It has a relatively high orbital eccentricity of 0.40 about the galaxy, ranging between 4.6 and 10.8 kiloparsecs from the core.
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AI Phoenicis is a variable star in the constellation of Phoenix. An Algol-type eclipsing binary, its apparent magnitude is constant at 8.58 for most of the time, sharply dropping to 9.35 during primary eclipse and to 8.89 during secondary eclipse. The system's variability was discovered by W. Strohmeier in 1972. From parallax measurements by the Gaia spacecraft, the system is located at a distance of from Earth, in agreement with earlier estimates based on its luminosity (173 ± 11 parsecs). The primary star is a K-type subgiant with a spectral type of K0IV and an effective temperature of 5,000 K, while the secondary is an F-type main sequence star with a spectral type of F7V and a temperature of 6,300 K. The primary component, while visually fainter, is slightly more luminous than the secondary due to its higher infrared output.
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The greatest problem biasing star counts is the extreme differences in inherent brightness of different sizes. Heavy, bright stars (both giants and blue dwarfs) are the most common stars listed in general star catalogs, even though on average they are rare in space. Small dim stars (red dwarfs) seem to be the most common stars in space, at least locally, but can only be seen with large telescopes, and then only when they are within a few tens of light-years from Earth. For example, the blue giant ζ Puppis is 400 million times more luminous than the nearest star, a red dwarf named Proxima, or α Centauri C. Even though Proxima is only 4.2 light-years away from us, it is so dim that it cannot be seen with the naked eye (one of its companions, α Centauri A, is visible).
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Eta Carinae A is not a typical LBV. It is more luminous than any other LBV in the Milky Way although possibly comparable to other supernova impostors detected in external galaxies. It does not currently lie on the S Doradus instability strip, although it is unclear what the temperature or spectral type of the underlying star actually is, and during its Great Eruption it was much cooler than a typical LBV outburst, with a middle-G spectral type. The 1890 eruption may have been fairly typical of LBV eruptions, with an early F spectral type, and it has been estimated that the star may currently have an opaque stellar wind, forming a pseudo-photosphere with a temperature of 9,000–10,000 K. Eta Carinae B is a massive luminous hot star, about which little else is known.
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Stars with less than are predicted to directly become white dwarfs when energy generation by nuclear fusion of hydrogen at their core comes to a halt, although no stars are old enough for this to have occurred. In stars more massive than , the hydrogen surrounding the helium core reaches sufficient temperature and pressure to undergo fusion, forming a hydrogen-burning shell and causing the outer layers of the star to expand and cool. The stage as these stars move away from the main sequence is known as the subgiant branch; it is relatively brief and appears as a gap in the evolutionary track since few stars are observed at that point. When the helium core of low-mass stars becomes degenerate, or the outer layers of intermediate-mass stars cool sufficiently to become opaque, their hydrogen shells increase in temperature and the stars start to become more luminous.
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Sketch of Hertzsprung–Russell diagram of a globular cluster, showing blue stragglers A blue straggler is a main-sequence star in an open or globular cluster that is more luminous and bluer than stars at the main sequence turnoff point for the cluster. Blue stragglers were first discovered by Allan Sandage in 1953 while performing photometry of the stars in the globular cluster M3. Standard theories of stellar evolution hold that the position of a star on the Hertzsprung–Russell diagram should be determined almost entirely by the initial mass of the star and its age. In a cluster, stars all formed at approximately the same time, and thus in an H–R diagram for a cluster, all stars should lie along a clearly defined curve set by the age of the cluster, with the positions of individual stars on that curve determined solely by their initial mass.
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The spectral type of MY Cephei is given in the General Catalogue of Variable Stars as M6–7 Iab, indicating the star is an intermediate-size luminous supergiant star, although most authors gives M7–M7.5 I. Classification is difficult because of the lack of comparable standard stars, but its spectrum appears to be later than M5, earlier than VX Sagittarii when at M9, and more luminous than M7 giant stars. MY Cephei is a very luminous, cool and large extreme supergiant star, with a luminosity more than 100,000 times that of the Sun () and a radius in excess of a thousand times the Sun's radius (). It is likely the most luminous, coolest, and the largest supergiant star in its open cluster, and occupies the upper-right hand corner of the Hertzsprung–Russell diagram. A 2018 paper gives the star a temperature of , corresponding a radius of based on a luminosity of .
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A star with a core mass slightly below this level—in the range of —will undergo a supernova explosion, but so much of the ejected mass falls back onto the core remnant that it still collapses into a black hole. If such a star is rotating slowly, then it will produce a faint supernova, but if the star is rotating quickly enough, then the fallback to the black hole will produce relativistic jets. The energy that these jets transfer into the ejected shell renders the visible outburst substantially more luminous than a standard supernova. The jets also beam high energy particles and gamma rays directly outward and thereby produce x-ray or gamma- ray bursts; the jets can last for several seconds or longer and correspond to long-duration gamma-ray bursts, but they do not appear to explain short- duration gamma-ray bursts.
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GG Tauri consists of four (possibly five) stars, which are T Tauri stars – a class of variable stars that show irregular changes in brightness. These stars are extremely young and more luminous than their main sequence counterparts, because they have not condensed into the normal size yet. The four components of GG Tauri stars are relatively cool K-type or M-type stars, with these spectral types: K7 for GG Tauri Aa, M0.5 for GG Tauri Ab, M5 for GG Tauri Ba, and M7 for GG Tauri Bb; the age of the system is estimated to be 1.5 million years. A dynamical study of the system found the masses of the four stars to be: for GG Tauri Aa, for GG Tauri Ab, for GG Tauri Ba, and for GG Tauri Bb. At , GG Tauri has a substellar mass and is a brown dwarf.
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Very-low-mass stars are fully convective and may continue to fuse hydrogen into helium for up to a trillion years until only a small fraction of the entire star is hydrogen. Luminosity and temperature steadily increase during this time, just as for more-massive main-sequence stars, but the length of time involved means that the temperature eventually increases by about 50% and the luminosity by around 10 times. Eventually the level of helium increases to the point where the star ceases to be fully convective and the remaining hydrogen locked in the core is consumed in only a few billion more years. Depending on mass, the temperature and luminosity continue to increase for a time during hydrogen shell burning, the star can become hotter than the Sun and tens of times more luminous than when it formed although still not as luminous as the Sun.
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A star with a core mass slightly below this level—in the range of —will undergo a supernova explosion, but so much of the ejected mass falls back onto the core remnant that it still collapses into a black hole. If such a star is rotating slowly, then it will produce a faint supernova, but if the star is rotating quickly enough, then the fallback to the black hole will produce relativistic jets. The energy that these jets transfer into the ejected shell renders the visible outburst substantially more luminous than a standard supernova. The jets also beam high energy particles and gamma rays directly outward and thereby produce x-ray or gamma-ray bursts; the jets can last for several seconds or longer and correspond to long-duration gamma-ray bursts, but they do not appear to explain short-duration gamma-ray bursts.
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The brightest stars in globular clusters such as NGC 288 are red giants Red giants were identified early in the 20th century when the use of the Hertzsprung–Russell diagram made it clear that there were two distinct types of cool stars with very different sizes: dwarfs, now formally known as the main sequence; and giants. The term red-giant branch came into use during the 1940s and 1950s, although initially just as a general term to refer to the red-giant region of the Hertzsprung–Russell diagram. Although the basis of a thermonuclear main-sequence lifetime, followed by a thermodynamic contraction phase to a white dwarf was understood by 1940, the internal details of the various types of giant stars were not known. In 1968, the name asymptotic giant branch (AGB) was used for a branch of stars somewhat more luminous than the bulk of red giants and more unstable, often large-amplitude variable stars such as Mira.
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Alberto Nero, resumed the major repairs and repainting of Our Lady's Basilica. The first move was to treat the whole church and complex with anti-termite chemicals to control and exterminate those destructive pests which have already attacked and damaged considerably both structures. By September 1994, the leaking roofs of the Basilica have been fully repaired and repainted, the damaged ceilings rehabilitated and repainted together with the interior walls of the Basilica, the electrical wirings and installations renovated, the gigantic and ugly chandeliers were replaced with the more luminous and more economical Highbay luminaire lamps, the Cross at the Basilica dome provided with a neon light tubes which distinguishes the Basilica at night even from afar and finally a 20 KVA standby power generator had been purchased and installed to provide emergency lights during brown-outs. On November 3, 1994, the repair works and repainting of the Basilica Minore's exterior walls were resumed.
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H–R diagram for globular cluster M5, with known AGB stars marked in blue, flanked by some of the more luminous red-giant branch stars, shown in orange The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (0.6–10 solar masses) late in their lives. Observationally, an asymptotic-giant-branch star will appear as a bright red giant with a luminosity ranging up to thousands of times greater than the Sun. Its interior structure is characterized by a central and largely inert core of carbon and oxygen, a shell where helium is undergoing fusion to form carbon (known as helium burning), another shell where hydrogen is undergoing fusion forming helium (known as hydrogen burning), and a very large envelope of material of composition similar to main-sequence stars.
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The distance to Eta Carinae has been determined by several different methods, resulting in a widely accepted value of 2,300 parsecs (7,800 light-years), with a margin of error around 100 parsecs (330 light- years). The distance to Eta Carinae itself cannot be measured using parallax due to its surrounding nebulosity, but other stars in the Trumpler 16 cluster are expected to be at a similar distance and are accessible to parallax. Gaia Data Release 2 has provided the parallax for many stars considered to be members of Trumpler 16, finding that the four hottest O-class stars in the region have very similar parallaxes with a mean value of 0.383 ± 0.017 milli- arcseconds (mas), which translates to a distance of 2,600 ± 100 parsecs. This implies that Eta Carinae may be more distant than previously thought, and also more luminous, although it is still possible that it is not at the same distance as the cluster or that the parallax measurements have large systematic errors.
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In 1997 Ruiz et al. had made two estimates of distance of Kelu-1—from its proper motion, assuming its observed motion is due to Solar System's motion only (about 12 parsecs), and from its apparent magnitude in J band, assuming it is same with that of GD 165 B—another L-type brown dwarf with similar spectral properties, discovered in 1988 in the system of white dwarf GD 165 (about 10 parsecs). But in 1999 preliminary trigonometric parallax of Kelu-1, measured under USNO faint-star parallax program, was obtained, and it turned out that it is located further—at about 19 parsecs, and so it is more luminous than GD 165 B. There were two possible explanations of overluminosity of Kelu-1: it is either young (age less than 0.1 Gyr) or binary. However, observations of Kelu-1 with near-infrared camera NICMOS on Hubble Space Telescope carried out on 1998 August 14, did not reveal the presence of any companion with separation greater than 300 mas and magnitude difference less than 6.7 mag.
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Their angular radii have been directly measured; in combination with the very accurate distance, this gives and for Aa and Ab respectively. Their surface temperatures can be calculated by comparison of observed and synthetic spectra, direct measurement of their angular diameters and brightnesses, calibration against their observed colour indices, and disentangling of high resolution spectra. Weighted averages of these four methods give 4,970 ± 50 K for Aa and 5,730 ± 60 for Ab. Their bolometric luminosities are most accurately derived from their apparent magnitudes and bolometric corrections, but are confirmed by calculation from the temperatures and radii of the stars. Aa is 78.7 ± 4.2 times as luminous as the Sun and Ab 72.7 ± 3.6 times as luminous, so the star defined as the primary component is the more luminous when all wavelengths are considered but very slightly less bright at visual wavelengths. Estimated to be 590 to 650 million years old, the stars were probably at the hot end of spectral class A during their main sequence lifetime, similar to Vega.
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The light in the blue region shows broad line features, while the red region shows continuous emission.Mystery object spied with Hubble The European Homepage for the NASA/ESA Hubble Space Telescope November 2008 update The spectrum shows a handful of spectral lines, but when astronomers try to trace any one of them to an element the other lines fail to match up with any other known elements. Because of its uncommon spectrum, the team was not able to determine the distance to the object using standard redshift techniques; it is not even known whether the object is within or outside the Milky Way. Furthermore, no Milky Way star or external galaxy has been detected at this location, meaning any source is very faint. The European X-ray satellite XMM Newton made an observation in early August 2006 which appears to show an X-ray glow around SCP 06F6,How they wonder what you are, Nature News, 19 September 2008 two orders of magnitude more luminous than that of supernovae.
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They moved beyond the flat perspective and outlined figuration of earlier painting in favour of three-dimensional pictorial spaces. The position of viewers and how they might relate to the scene became important for the first time; in the Arnolfini Portrait, Van Eyck arranges the scene as if the viewer has just entered the room containing the two figures.Smith (2004), 58–60 Advancements in technique allowed far richer, more luminous and closely detailed representations of people, landscapes, interiors and objects.Jones (2011), 9 Dieric Bouts's The Entombment, c. 1440–55 (National Gallery, London), is an austere but affecting portrayal of sorrow and grief, and one of the few surviving 15th-century glue-size paintings.Campbell (1998), 39–41 Although, the use of oil as a binding agent can be traced to the 12th century, innovations in its handling and manipulation define the era. Egg tempera was the dominant medium until the 1430s, and while it produces both bright and light colours, it dries quickly and is a difficult medium in which to achieve naturalistic textures or deep shadows. Oil allows smooth, translucent surfaces and can be applied in a range of thicknesses, from fine lines to thick broad strokes.
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Polaris is the brightest Cepheid variable star visible from Earth. It is a triple star system, the supergiant primary star having two yellow-white main-sequence star companions that are 17 and 2,400 astronomical units (AU) distant and take 29.6 and 42,000 years respectively to complete one orbit. Traditionally called Kochab, Beta Ursae Minoris at apparent magnitude 2.08 is only slightly less bright than Polaris. Located around 131 light-years away from Earth, it is an orange giant—an evolved star that has used up the hydrogen in its core and moved off the main sequence—of spectral type K4III. Slightly variable over a period of 4.6 days, Kochab has had its mass estimated at 1.3 times that of the Sun via measurement of these oscillations. Kochab is 450 times more luminous than the Sun and has 42 times its diameter, with a surface temperature of approximately 4,130 K. Estimated to be around 2.95 billion years old, give or take 1 billion years, Kochab was announced to have a planetary companion around 6.1 times as massive as Jupiter with an orbit of 522 days. Ursa Minor and Ursa Major in relation to Polaris.
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Supernovae types depending on initial mass and metallicity The overwhelming probability is that the next supernova observed in the Milky Way will originate from an unknown white dwarf or anonymous red supergiant, very likely not even visible to the naked eye. Nevertheless, the prospect of a supernova originating from an object as extreme, nearby, and well-studied as Eta Carinae arouses great interest. As a single star, a star originally around 150 times as massive as the Sun would typically reach core collapse as a Wolf–Rayet star within 3 million years. At low metallicity, many massive stars will collapse directly to a black hole with no visible explosion or a sub-luminous supernova, and a small fraction will produce a pair-instability supernova, but at solar metallicity and above there is expected to be sufficient mass loss before collapse to allow a visible supernova of type Ib or Ic. If there is still a large amount of expelled material close to the star, the shock formed by the supernova explosion impacting the circumstellar material can efficiently convert kinetic energy to radiation, resulting in a superluminous supernova (SLSN) or hypernova, several times more luminous than a typical core collapse supernova and much longer-lasting.
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