Casino's instrumental music often projects an initial illusion of formlessness, all the better to surprise you with sneak details later, and Moon Trip Radio reaches a new level of feigned nebulosity.
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Unlike both the two nearby LBVs, V4650 Sgr has no detectable associated nebulosity.
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This produces the complex nebulosity that appears like a stem of a rosebud.
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Hubble Space Telescope image of reflection nebulosity near Merope (IC 349) With larger amateur telescopes, the nebulosity around some of the stars can be easily seen; especially when long- exposure photographs are taken. Under ideal observing conditions, some hint of nebulosity around the cluster may even be seen with small telescopes or average binoculars. It is a reflection nebula, caused by dust reflecting the blue light of the hot, young stars. Amateur astrophotography of the Seven Sisters.
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GK Persei: Nova of 1901 Some novae leave behind visible nebulosity, material expelled in the nova explosion or in multiple explosions.
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Also known as Pickering's Wedge, or Pickering's Triangular Wisp, this segment of relatively faint nebulosity was discovered photographically in 1904 by Williamina Fleming at Harvard Observatory, where Edward Charles Pickering was director at the time. The Triangle is brightest along the northern side of the loop, though photographs show the nebulosity extending into the central area as well.
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The astronomer William Herschel made a detailed catalog of nebulosity and clusters, and in 1781 discovered the planet Uranus, the first new planet found.
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During much of their work, William Herschel believed that these nebulae were merely unresolved clusters of stars. In 1790, however, he discovered a star surrounded by nebulosity and concluded that this was a true nebulosity, rather than a more distant cluster. Beginning in 1864, William Huggins examined the spectra of about 70 nebulae. He found that roughly a third of them had the emission spectrum of a gas.
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The Pleiades are an example of a cluster which has 'boiled away' the H II region from which it was formed. Only a trace of reflection nebulosity remains.
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M73 was discovered by Charles Messier on October 4, 1780, who originally described the object as a cluster of four stars with some nebulosity. Subsequent observations by John Herschel, however, failed to reveal any nebulosity. Moreover, Herschel noted that the designation of M73 as a cluster was questionable. Nonetheless, Herschel included M73 in his General Catalogue of clusters, nebulae, and galaxies, and John Dreyer included M73 when he compiled the New General Catalogue.
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The distance to CK Vulpeculae cannot be determined accurately. Assumptions about its maximum possible luminosity and a position beyond known nebulosity give a distance of . Measurements of the expansion of the nebulosity assumed to have been produced in 1670 give a distance of . There are gas clouds at 500 pc and 2 kpc, but only the first is detected in the spectrum of CK Vulpeculae, placing strong constraints on the possible distance.
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Other observations at around the same time described a strongly orange central region in a larger fainter green nebulosity. One paper described it as looking like a "red spade-beard".
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Born in 1920 in Wheeling, West Virginia, Herbig received his Ph.D in 1948 at the University of California, Berkeley; his dissertation is entitled A Study of Variable Stars in Nebulosity.
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The star's spectrum is unusual in that it contains very strong emission lines resulting from surrounding nebulosity. W Cygni is a semi-regular variable red giant star, 618 light-years from Earth.
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Under the Trumpler scheme, the Pleiades are classified as I3rn (strongly concentrated and richly populated with nebulosity present), while the nearby Hyades are classified as II3m (more dispersed, and with fewer members).
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These disks are created by an ejection of material roughly every ten years, which then settles into the equatorial plane about the star. However, the bright nebulosity that surrounds this star makes the observation uncertain.
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The last definite detection of the comet was made on June 7, when it appeared as a faint, ill-defined nebulosity. Increasing moonlight and the comet's decreasing brightness prevented any further visual sightings of the comet.
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That object and another star are thought to be seen though dense nebulosity associated with CK Vulpeculae which causes them to vary dramatically in brightness. CK Vulpeculae now consists of a compact central object with gas flowing out at approximately into a bipolar nebula. A 15" path of nebulosity seen in the 1980s lies at the centre of a 70" bipolar nebula. A compact radio source is seen at the centre of this nebula, and an infrared point source, but it has not been detected at optical wavelengths.
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Hubble Space Telescope image showing the bipolar Homunculus Nebula which surrounds Eta Carinae Two eruptions have been observed from Eta Carinae, the Great Eruption of the mid 19th century and the Lesser Eruption of 1890. In addition, studies of outlying nebulosity suggest at least one earlier eruption around AD 1250. A further eruption may have occurred around AD 1550, although it is possible that the material indicating this eruption is actually from the Great Eruption slowed down by colliding with older nebulosity. The mechanism producing these eruptions is unknown.
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IC 2948 is the brightest emission and reflection nebulae towards the southeast, while IC 2944 is the cluster of stars and surrounding nebulosity stretching towards λ Centauri. Other designations for IC 2872 include RCW 60, G39, and G40.
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A larger amateur instrument reveals 8 more stars, nebulosity to the east and west of the cluster, and a diameter of 9 arcminutes. The nebulosity in this region is part of the Gamma Cygni Nebula. The other stars, approximately 3700 light-years from Earth, are mostly blue-white and very hot. Other open clusters in Cygnus include Dolidze 9, Collinder 421, Dolidze 11, and Berkeley 90. Dolidze 9, 2800 light-years from Earth and relatively young at 20 million light-years old, is a faint open cluster with up to 22 stars visible in small and medium-sized amateur telescopes.
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It, too, has nebulosity in the east. Collinder 421 is a particularly old open cluster at an age of approximately 1 billion years; it is of magnitude 10.1. 3100 light- years from Earth, more than 30 stars are visible in a diameter of 8 arcseconds.
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NGC 3572 plus nebulosity. V533 Car is the brightest star in the frame, on the right (south is up). V533 Carinae is a bright supergiant with a luminosity around 100,000 times that of the sun. The temperature is over 8,000 K and the radius around .
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A nearby corkscrew-shaped jet of nebulosity could have been expelled during the orbital motion. which would imply a period of 800 - 1,400 days. It is surrounded by a small cluster of stars around in total, separate from the much more massive Quintuplet Cluster.
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The companion is an A-type main-sequence star with a stellar classification of A3V and visual magnitude 9.2. As of 2008, it had an angular separation of from the primary. There is a faint infrared nebulosity at a separation of from the pair that is most likely a bow shock.
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Where yellow supergiants have surface gravities (log g) below about 2, the yellow hypergiants have log g around zero. In addition they pulsate irregularly, producing small variations in temperature and brightness. This produces very high mass loss rates, and nebulosity is common around the stars. Occasional larger outbursts can temporarily obscure the stars.
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The brightest nebulosity, later listed as NGC 1977, was discovered by William Herschel in 1786. He catalogued it as "H V 30" and described "!! 42 Orionis and neb[ula]". The two smaller reflection nebulae were first noted by German astronomer Heinrich Louis d'Arrest, NGC 1973 in 1862 and NGC 1975 in 1864.
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Faint nebulosity was discovered around WR 102 in 1981 and was identified as a wind-blown bubble. In 1982, a set of five luminous stars with highly ionised oxygen emission lines, including WR 102, was used to define the WO class of Wolf–Rayet stars. They were identified as highly evolved massive stars.
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The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures. It is a rather faint object located about 2 degrees SW of Sadr. For most telescopes it requires a UHC or OIII filter to see. Under favorable circumstances a telescope as small as 8 cm (with filter) can see its nebulosity.
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Orion variables are young, hot pre–main-sequence stars usually embedded in nebulosity. They have irregular periods with amplitudes of several magnitudes. A well-known subtype of Orion variables are the T Tauri variables. Variability of T Tauri stars is due to spots on the stellar surface and gas-dust clumps, orbiting in the circumstellar disks.
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SPHERE and VLT NACO image of the nebulosity forming around L2 Puppis (Credit: ESO/P. Kervella) L2 Puppis (also known as HD 56096) is a giant star in the constellation of Puppis and is located between the bright stars Canopus and Sirius. It is a semi-regular pulsating star. The designation L2 has a tangled history.
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The Cone Nebula is an H II region in the constellation of Monoceros. It was discovered by William Herschel on December 26, 1785, at which time he designated it H V.27. The nebula is located about 830 parsecs or 2,700 light- years away from Earth. The Cone Nebula forms part of the nebulosity surrounding the Christmas Tree Cluster.
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Identification on historical photographic plates showed possible irregular variations of about a magnitude before 1925, followed by a smooth gradual increase in brightness from magnitude 15 to brighter than magnitude 14 by 1976. Some authors had grouped IRC+10420 with the proto-planetary nebulae because of the surrounding nebulosity, but it was widely recognised as a highly luminous supergiant.
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The luminosity class as determined from different spectral features varies from bright giant (II) to bright supergiant (Ia), with a compromise being given as M5eIbp. Early attempts at classification were confused by the interpretation of surrounding nebulosity as companion stars. The derived spectral class varies depending on the features examined. The spectral features also vary noticeably over time.
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NGC 6193 (also known as Caldwell 82) is open cluster containing 27 stars in the constellation Ara, visible to the unaided eye. NGC 6193 lies at the center of the Ara OB1 association, which extends over a square degree. The cluster is associated with (and provides the energizing radiation for) neighboring regions of the nebulosity NGC 6188.
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The prominent star in the north of the cluster has a golden color, whereas the stars in the south of the cluster appear orange. Collinder 421 appears to be embedded in nebulosity, which extends past the cluster's borders to its west. Berkeley 90 is a smaller open cluster, with a diameter of 5 arcminutes. More than 16 members appear in an amateur telescope.
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NGC 6820 is a small reflection nebula near the open cluster NGC 6823 in Vulpecula. The reflection nebula and cluster are embedded in a large faint emission nebula called Sh 2-86. The whole area of nebulosity is often referred to as NGC 6820. M27, the Dumbbell Nebula, is found three degrees to the east, and α Vulpeculae three degrees to the west.
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Images of NGC 3132 reveal two stars close together within the nebulosity, one of 10th magnitude, the other 16th. The central planetary nebula nucleus (PNN) or white dwarf central star is the fainter of these two stars. This hot central star of about 100,000 K has now blown off its layers and is making the nebula fluoresce brightly from the emission of its intense ultraviolet radiation.
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It is a blue-white star of the main sequence, having an absolute magnitude of -0.99 and its positive radial velocity indicates that the star is moving away from the solar system. The star appears wrapped in an extensive nebulosity that partly shines by reflection and partly by emission. The reflection nebula is listed as GN 05.19.0 and the HII region is called Sh2-263.
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When the nova was discovered, its spectrum showed material moving at a high speed towards Earth. However, when the spectrum was examined again in August 1892, it appeared to be a planetary nebula. Observations at the Lick Observatory by Edward Emerson Barnard showed it to be disc-shaped, with clear nebulosity in a diameter of 3 arcseconds. The shell had a diameter of 12 arcseconds in 1943.
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With a magnitude of 6.5, M21 is not visible to the naked eye; however, with the smallest binoculars it can be easily spotted on a dark night. The cluster is positioned near the Trifid nebula (NGC 6514), but is not associated with that nebulosity. It forms part of the Sagittarius OB1 association. This cluster is located away from Earth with an extinction of 0.87.
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Even so, it radiates about as much energy in 20 seconds as the Sun does in a year. A close point source has been discovered hidden in the surrounding nebulosity, but there has been no confirmation of this being a star or whether it is physically associated. The Pistol Star is the brightest star in this image of the Quintuplet cluster, just below centre.
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The linear diameter was estimated at only 11 light years. Its Trumpler class is III,3,p,n (as it is associated with nebulosity), although Götz gives, differently, II,3,m, and Kepple/Sanner gives I,2,m,n. The Sky Catalogue 2000.0 lists it with 50 member stars; earlier Becvar gave only the number of 20 members. This cluster can be seen in binoculars.
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A few fainter stars are around them, but the cluster appears quite isolated, especially in smaller telescopes. In photographs, many faint Milky Way background stars appear. Messier 29 can be found quite easily as it is about 1.7 degrees south and a little east of Gamma or 37 Cygni (Sadr). In the vicinity of Messier 29, there is some diffuse nebulosity which can be detected in photographs.
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Some confusion surrounds what Bayer intended by these designations. It is sometimes claimed that Bayer could not have resolved the pair into two patches of nebulosity, and that Chi refers to the Double Cluster and h to a nearby star.Stephen James O'Meara and Daniel W.E. Green, 2003, "The Mystery of the Double Cluster", Sky and Telescope, Vol. 105, No. 2 (February 2003), p. 116–119.
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Symbiotic binaries are often divided into two sub-types based on the nature of the continuum in their spectra. S-type systems have a stellar continuum since the giant component is not obscured. D-type systems are surrounded by optically thick dusty nebulosity and the star itself is not directly visible. D-type systems tend to contain a Mira variable or other long period variable star.
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NGC 7380 is a young open cluster of stars in the northern circumpolar constellation of Cepheus, discovered by Caroline Herschel in 1787. The surrounding emission nebulosity is known colloquially as the Wizard Nebula, which spans an angle of . German-born astronomer William Herschel included his sister's discovery in his catalog, and labelled it H VIII.77. The nebula is known as S 142 in the 1959 Sharpless catalog (Sh2-142).
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It is best observed using a telescope with an aperture of at least , but even a telescope will reveal its elliptical ring shape. The interior hole can be resolved by a instrument at a magnification of 100×. Larger instruments will show a few darker zones on the eastern and western edges of the ring, and some faint nebulosity inside the disk. The central star, at magnitude 14.8, is difficult to spot.
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M57 is an example of the class of planetary nebulae known as bipolar nebulae, whose thick equatorial rings visibly extend the structure through its main axis of symmetry. It appears to be a prolate spheroid with strong concentrations of material along its equator. From Earth, the symmetrical axis is viewed at about 30°. Overall, the observed nebulosity has been currently estimated to be expanding for approximately 1,610 ± 240 years.
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IC 1590 is an open cluster located in the nebulosity of NGC 281. 279 stars with magnitudes less than or equal to 17 are visible within or near the cluster. The cluster is estimated to be 3.5 million years old, making it relatively young compared to other star systems. Inside the cluster is a multiple-star system that emits light which helps give the dust in NGC 281 its glow.
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It will produce a type Ib or Ic supernova within the next few hundred thousand years. WR 102c is surrounded by a shell of nebulosity which contains dust made even hotter than the star itself by intense radiation. The nebula also includes nearly of molecular hydrogen and around of ionised hydrogen, all expelled from the star. There is a suggestion that WR 102c may be a binary star.
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Discussing the location of the Orion Nebula, what is seen within the star-formation region, and the effects of interstellar winds in shaping the nebula Amateur image of the Orion Nebula taken with a mid-range digital camera Orion and Running Man nebulae and nebulosity imaged in LRGB 384 mm refractor The constellation of Orion with the Orion Nebula (lower middle) The Nebula is visible with the naked eye even from areas affected by some light pollution. It is seen as the middle "star" in the "sword" of Orion, which are the three stars located south of Orion's Belt. The star appears fuzzy to sharp-eyed observers, and the nebulosity is obvious through binoculars or a small telescope. The peak surface brightness of the central region is about 17 Mag/arcsec2 (about 14 milli nits) and the outer bluish glow has a peak surface brightness of 21.3 Mag/arcsec2 (about 0.27 millinits).. The conversion to nits is based on 0 magnitude being 2.08 microlux.
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Its local geometry is similar to the Orion Nebula except that it is viewed edge-on rather than face-on.. The open cluster NGC 6618 lies embedded in the nebulosity and causes the gases of the nebula to shine due to radiation from these hot, young stars; however, the actual number of stars in the nebula is much higher - up to 800, 100 of spectral type earlier than B9, and 9 of spectral type O, plus over a thousand stars in formation on its outer regions. It is also one of the youngest clusters known, with an age of just 1 million years. The luminous blue variable HD 168607, located in the south-east part of the Omega nebula, is generally assumed to be associated with it; its close neighbor, the blue hypergiant HD 168625, may be too. The Swan portion of M17, the Omega Nebula in the Sagittarius nebulosity is said to resemble a barber's pole.
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NGC 2392 in 32 inch telescope The nebula was discovered by William Herschel on January 17, 1787, in Slough, England. He described it as "A star 9th magnitude with a pretty bright middle, nebulosity equally dispersed all around. A very remarkable phenomenon."The Scientific Papers of Sir William Herschel by J. L. E. Dreyer, Royal Society, London 1912 NGC 2392 WH IV-45 is included in the Astronomical League's Herschel 400 observing program.
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The ESO Very Large Telescope image on the right is a close up of a set of Bok globules discovered in IC 2944 by astronomer A. David Thackeray in 1950. These globules are now known as Thackeray's Globules. In 2MASS images, 6 stars are visible within the largest globule. The region of nebulosity visible in modern images includes both IC 2944 and IC 2948, as well as the fainter IC 2872 nearby.
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T Tauri is a variable star in the constellation Taurus, the prototype of the T Tauri stars. It was discovered in October 1852 by John Russell Hind. T Tauri appears from Earth amongst the Hyades cluster, not far from ε Tauri; but it is actually 420 light years behind it and was not formed with the rest of them. Faint nebulosity around T Tauri is a Herbig–Haro object called Burnham's Nebula or HH 255.
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CE Cam and the surrounding nebulosity at infrared wavelengths (Credit: NASA/JPL-Caltech/UCLA) HD 21389 is a supergiant variable star in reflection nebula VdB 15, in the constellation Camelopardalis. It is part of the Camelopardalis OB1 association. The near-identical member CS Camelopardalis lies half a degree to the north. Since 1943, the spectrum of CE Cam has served as one of the stable anchor points by which other stars are classified.
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The resulting nebula contains material from both stars and is complex in nature. From 1997 until 2015, AG Pegasi entered a quiescent phase with no further change to its brightness. Then the hot component increased in temperature, which caused the nebulosity around the stars to become more ionised and increase in brightness. The combination of the extremely slow nova and smaller outburst means that Z Andromedae is classed as a symbiotic nova.
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It was nearest the Earth on October 10, 1858, and for much of October was a brilliant object with a long, scimitar-like dust tail and prominent gas tail. It remained a naked-eye object until November for Southern Hemisphere observers. The final observation was by William Mann, chief assistant at the Royal Observatory, Cape of Good Hope, who detected it as a faint nebulosity on March 4, 1859.Kronk, Cometography, v.
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It is naturally very bright but is almost hidden in the radiance of Merope.Merope, Star-Names and their meanings, Richard Hinckley Allen, Dover Publications, 1963,pg. 406. It appears blue in photographs because of the fine carbon dust spread throughout the cloud. Though it was once thought the Pleiades formed from this and surrounding nebulae, it is now known that the Pleiades nebulosity is caused by a chance encounter with the cloud.
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The easiest segment to find is 6960, which runs behind 52 Cygni, a star that can be seen with the naked eye. NGC 6992/5 are objects on the eastern side of the loop which are also relatively easy to see. NGC 6974 and NGC 6979 are visible as knots in an area of nebulosity along the northern rim. Pickering's Triangle is much fainter, and has no NGC number (though 6979 is occasionally used to refer to it).
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It is the brightest star of class O in the night sky. Alnitak Ab is a blue subgiant of spectral type B1IV with an absolute magnitude of -3.9 and an apparent magnitude of 4.3, discovered in 1998. A fourth star, 9th magnitude Alnitak C, has not been confirmed to be part of the Aa-Ab-B group, and may simply lie along the line of sight. The Alnitak system is bathed in the nebulosity of IC 434.
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Intense study of large numbers of stars suggest that 6.7% of stars with temperatures between and show rapid small-amplitude pulsations but are not members of other variable star classes. These are potentially Maia variables. Maia is surrounded by the Maia Nebula (also known as NGC 1432), a reflection nebula that is one of the brightest patches of nebulosity within the Pleiades star cluster. It is the only member of the New General Catalogue discovered photographically.
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The Carina Nebula (catalogued as NGC 3372; also known as the Grand Nebula, Great Nebula in Carina, or Eta Carinae Nebula) is a large, complex area of bright and dark nebulosity in the constellation Carina, and is located in the Carina–Sagittarius Arm. The nebula is approximately from Earth. The nebula has within its boundaries the large Carina OB1 association and several related open clusters, including numerous O-type stars and several Wolf–Rayet stars. encompasses the star clusters and .
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NGC 6188 is an emission nebula located about 4,000 light years away in the constellation Ara. The bright open cluster NGC 6193, visible to the naked eye, is responsible for a region of reflection nebulosity within NGC 6188. NGC 6188 is a star forming nebula, and is sculpted by the massive, young stars that have recently formed there – some are only a few million years old. This spark of formation was probably caused when the last batch of stars went supernova.
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N76A is the small dense HII region SE of AB7, part of the "ring", while AB7 lies at the centre of the less dense nebulosity within the ring. It may already be the home of a new generation of stars; N76A hosts at least five hot young stars, including a probable O9 main sequence star at its centre. A nearby unusual oxygen-rich supernova remnant has been intensively studied. It is visible as the knot of filaments growing green from ionised oxygen emission.
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The clusters were designated h Persei and χ Persei by Johann Bayer in his Uranometria (1603). It is sometimes claimed that Bayer could not have resolved the pair into two patches of nebulosity, and that χ refers to the Double Cluster and h to a nearby star. Bayer's Uranometria chart for Perseus does not show them as nebulous objects, but his chart for Cassiopeia does, and they are described as Nebulosa Duplex in Schiller's Coelum Stellatum Christianum, which was assembled with Bayer's help.
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Portion of the Carina Nebula Around 150 AD, Ptolemy recorded, in books VII–VIII of his Almagest, five stars that appeared nebulous. He also noted a region of nebulosity between the constellations Ursa Major and Leo that was not associated with any star. The first true nebula, as distinct from a star cluster, was mentioned by the Persian astronomer Abd al-Rahman al-Sufi, in his Book of Fixed Stars (964). He noted "a little cloud" where the Andromeda Galaxy is located.
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V838 Monocerotis may be a post-asymptotic giant branch star, on the verge of its death. The nebulosity illuminated by the light echo may actually be shells of dust surrounding the star, created by the star during previous similar outbursts. The brightening may have been a so-called helium flash, where the core of a dying low-mass star suddenly ignites helium fusion disrupting, but not destroying, the star. Such an event is known to have occurred in Sakurai's Object.
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WR 31a was first published in 1952 as one of six peculiar emission line stars, but not given a designation at that time. It was described as having numerous P Cygni type lines with unusually broad emission components. A year later it was listed as being associated with nebulosity, at the time thought to be a planetary nebula. In 1976, it was included in a catalogue of southern emission-line stars, the third catalogue of emission objects compiled by Karl Gordon Henize.
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In 1914, Eta Carinae was reported to have a faint companion and also to be non-stellar. Observations in 1944 and 1945 showed a somewhat elongated nebulosity around wide and long. It was measured to be expanding at a rate which was consistent with having originated in an explosion in the mid 19th century. At that time the shape of the nebula showed a central bulge with a single large lump to the northwest and two smaller extensions to the southeast, which was described as a Homunculus.
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Hubble The spectrum of the Homunculus is complex, consisting of reflected, thermal, and emission components at wavelengths across the electromagnetic spectrum. The dominant feature is blackbody radiation from dust heated by the stars within. Overlaid on this is some light from the stars themselves reflected mostly from dense features within the nebulosity, showing strong visual and UV spectral lines in emission. There are also emission lines from ionised gas where it collides with slower moving material or is excited by high energy electromagnetic radiation from the stars.
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The name "Cave Nebula" was coined for this object by Patrick Moore, presumably derived from photographic images showing a curved arc of emission nebulosity corresponding to a cave mouth. The name was also used earlier to refer to another brighter but unrelated reflection nebula in Cepheus known as Ced 201 or VdB 152, positioned at R.A.: 22h 13m 27s Dec.: +70° 15′ 18″ (2000). The name's application to Sh2-155 has come into vogue through the nebula's inclusion in Moore's Caldwell catalogue as object Caldwell 9.
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Herbig–Haro (HH) objects are bright patches of nebulosity associated with newborn stars. They are formed when narrow jets of partially ionised gas ejected by stars collide with nearby clouds of gas and dust at several hundred kilometres per second. Herbig–Haro objects are commonly found in star-forming regions, and several are often seen around a single star, aligned with its rotational axis. Most of them lie within about one parsec (3.26 light-years) of the source, although some have been observed several parsecs away.
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9 Sgr is the main source of ionisation for much of the visible nebulosity in the region, although the young O star Herschel 36 ionises the dense Hourglass Nebula region. 9 Sgr itself is surrounded by an ionised HII region about 30 light years across including the reflection nebulae NGC 6523 and NGC 6533. This ionised region lies in front of a denser molecular cloud. The distances to 9 Sgr, M8, and NGC 6530 are uncertain, but generally estimated to be between 1,200 and 1,800 parsecs.
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The secondary star has been estimated to be around 0.6 times as massive as the Sun, making it an orange dwarf of spectral type K5. Also known as a donor star, the secondary supplies mass to the white dwarf via its accretion disc. A small nebulous disc was reported around the nova and this led to it being listed in the New General Catalogue as a possible planetary nebula. No nebulosity is visible in modern observations and the Revised New General Catalogue lists this as a "non-existent" object.
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Nebulosity is visible to the north and east of the cluster, which is 7 arcminutes in diameter. The brightest star appears in the eastern part of the cluster and is of the 7th magnitude; another bright star has a yellow hue. Dolidze 11 is an open cluster 400 million years old, farthest away of the three at 3700 light-years. More than 10 stars are visible in an amateur instrument in this cluster, of similar size to Dolidze 9 at 7 arcminutes in diameter, whose brightest star is of magnitude 7.5.
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The Small Sagittarius Star Cloud (also known as Messier 24 and IC 4715) is a star cloud in the constellation of Sagittarius, approximately 600 light years wide, which was discovered by Charles Messier in 1764. It should not be confused with the nearby Large Sagittarius Star Cloud which lies about 10° to the south. The stars, clusters and other objects comprising M24 are part of the Sagittarius or Sagittarius-Carina arms of the Milky Way galaxy. Messier described M24 as a "large nebulosity containing many stars" and gave its dimensions as being some 1.5° across.
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The French chose a female astronomer - Dorothea Klumpke - to be the one to ride in a balloon to observe the shower - the shower turned out a complete failure. Five years after meeting, Dorothea and Isaac were married in 1901 and stayed at his Sussex home. Dorothea left her job at the Paris Observatory in order to be with Isaac, whom she assisted in a project to photograph all 52 of the Herschel "areas of nebulosity." Their marriage ended after only a short while with Isaac's death in 1904.
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Dorothea inherited all his astronomical effects and a considerable fortune. Dorothea remained at the Sussex home and completed photography of the 52 areas, after which she went to stay with her mother and sister, Anna, at Chateau Rosa Bonheur, taking along the entire set of photographic plates. She returned to Paris Observatory and spent 25 years processing the plates and Isaac's notes, periodically publishing papers on the results. In 1929 she published a comprehensive catalogue of the survey "The Isaac Roberts Atlas of 52 Regions, a Guide to William Herschel's Fields of Nebulosity".
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The expansion rate of different portions of the nebula varies from 10 km/s to at least 30 km/s, leading to age estimates of 78,500 - 236,000 years. The nebula has been studied at radio and x-ray wavelengths, but it is still unclear whether it was produced at the class O main sequence stage of development, as a red supergiant, luminous blue variable, or mainly as a Wolf- Rayet star. NGC 2361 is a bright knot of nebulosity on one edge of the central ring of NGC 2359.
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NGC 2060 is a star cluster within the Tarantula Nebula in the Large Magellanic Cloud, very close to the larger NGC 2070 cluster containing R136. It was discovered by John Herschel in 1836. It is a loose cluster approximately 10 million years old, within one of the Tarantula Nebula's superbubbles formed by the combined stellar winds of the cluster or by old supernovae. NGC 2060 is often used synonymously for the supernova remnant N157B (30 Doradus B) which is a larger area of faint nebulosity and strong radio emission.
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He also cataloged the Omicron Velorum star cluster as a "nebulous star" and other nebulous objects, such as Brocchi's Cluster. The supernova that created the Crab Nebula, the SN 1054, was observed by Arabic and Chinese astronomers in 1054. In 1610, Nicolas-Claude Fabri de Peiresc discovered the Orion Nebula using a telescope. This nebula was also observed by Johann Baptist Cysat in 1618. However, the first detailed study of the Orion Nebula was not performed until 1659, by Christiaan Huygens, who also believed he was the first person to discover this nebulosity.
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IC 2177 is a region of nebulosity that lies along the border between the constellations Monoceros and Canis Major. It is a roughly circular H II region centered on the Be star HD 53367. This nebula was discovered by Welsh amateur astronomer Isaac Roberts and was described by him as "pretty bright, extremely large, irregularly round, very diffuse." The name Seagull Nebula is sometimes applied by amateur astronomers to this emission region, although it more properly includes the neighboring regions of star clusters, dust clouds and reflection nebulae.
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Following the Great Eruption, Eta Carinae became self-obscured by the ejected material, resulting in dramatic reddening. This has been estimated at four magnitudes at visual wavelengths, meaning the post-eruption luminosity was comparable to the luminosity when first identified. Eta Carinae is still much brighter at infrared wavelengths, despite the presumed hot stars behind the nebulosity. The recent visual brightening is considered to be largely caused by a decrease in the extinction, due to thinning dust or a reduction in mass loss, rather than an underlying change in the luminosity.
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Observations show the bright nebulosity has temperatures between and , whose densities average of about particles per cubic centimetre. Its outer halo has the higher temperature around , but is of much lower density. Velocity of the fast stellar wind is about , where spectroscopic analysis shows the current rate of mass loss averages solar masses per year, equivalent to twenty trillion tons per second (20 Eg/s). An optical image of the nebula's surrounding halo Surface temperature for the central PNN is about , being times as luminous as the sun.
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Both stars are members of Scorpius-Centaurus Association or the smaller portion known as the Lower Centaurus Crux subgroup. The double star forms the nucleus of the very young Epsilon Chamaeleontis stellar group which comprises about twenty stars. The nebulosity and star formation occurring in this region is currently a very important line of study in the southern hemisphere, whose proximity to the Sun is yielding new astrophysical information. Several papers have been published in the last few years on Lower Centaurus Crux subgroup of stars in the far southern constellations of Musca, Chamaeleon and Octans holding the south celestial pole.
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Lying adjacent to the nebulosity is the globular cluster known as NGC 6723, which is actually in the neighbouring constellation of Sagittarius and is much much further away. Near Epsilon and Gamma Coronae Australis is Bernes 157, a dark nebula and star forming region. It is a large nebula, 55 by 18 arcminutes, that possesses several stars around magnitude 13. These stars have been dimmed by up to 8 magnitudes by its dust clouds. IC 1297 is a planetary nebula of apparent magnitude 10.7, which appears as a green-hued roundish object in higher-powered amateur instruments.
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Elvius's first publications were articles she co-authored with John S. Hall and published in the Lowell Observer, a quarterly newsletter of Lowell Observatory. The first was an article published in 1964 titled "Polarimetric observations of NGC 5128 (Cent A) and other extragalactic objects." It was followed two years later in 1966 by "Observations of the color and polarization of the reflection nebulae NGC 2068, NCG 7023 and the Merope Nebula obtained in three spectral regions." Their next article was "Observations of polarization and color in the nebulosity associated with the Pleiades cluster," which was published on 8 September 1967.
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NGC 772, with a notated supernova NGC 772 is a spiral galaxy with an integrated magnitude of 10.3, located southeast of β Arietis and 15 arcminutes west of 15 Arietis. It is a relatively bright galaxy and shows obvious nebulosity and ellipticity in an amateur telescope. It is 7.2 by 4.2 arcminutes, meaning that its surface brightness, magnitude 13.6, is significantly lower than its integrated magnitude. NGC 772 is a class SA(s)b galaxy, which means that it is an unbarred spiral galaxy without a ring that possesses a somewhat prominent bulge and spiral arms that are wound somewhat tightly.
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92 minutes of exposure time. (RC10, ASI2400MC, EQ6-R) It was formerly thought that the dust was left over from the formation of the cluster, but at the age of about 100 million years generally accepted for the cluster, almost all the dust originally present would have been dispersed by radiation pressure. Instead, it seems that the cluster is simply passing through a particularly dusty region of the interstellar medium. Studies show that the dust responsible for the nebulosity is not uniformly distributed, but is concentrated mainly in two layers along the line of sight to the cluster.
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BD+60°2522 is a bright O-Type star that has produced the Bubble Nebula (NGC 7635) with its stellar wind. The exact classification of the star is uncertain, with a number of spectral peculiarities and inconsistencies between the appearance of the star itself and the effects on the nearby nebulosity, but it is undoubtedly a highly luminous hot massive star. Direct spectroscopy yields a spectral class of O6.5 and an effective temperature around 37,500K. It is a member of the Cassiopeia OB2 stellar association in the Perseus Arm of the galaxy at about 8,500 light-years' distance.
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Annotated image of Carina Nebula Eta Carinae is found within the Carina Nebula, a giant star-forming region in the Carina–Sagittarius Arm of the Milky Way. The nebula is a prominent naked eye object in the southern skies showing a complex mix of emission, reflection, and dark nebulosity. Eta Carinae is known to be at the same distance as the Carina Nebula and its spectrum can be seen reflected off various star clouds in the nebula. The appearance of the Carina Nebula, and particularly of the Keyhole region, has changed significantly since it was described by John Herschel over years ago.
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3C48 is a quasar discovered in 1960; it was the second source conclusively identified as such. 3C48 was the first source in the Third Cambridge Catalogue of Radio Sources for which an optical identification was found by Allan Sandage and Thomas A. Matthews in 1960 through interferometry. Jesse L. Greenstein and Thomas Matthews found that it had a redshift of 0.367, making it one of the highest redshift sources then known. It was not until 1982 that the surrounding faint galactic "nebulosity" was confirmed to have the same redshift as 3C48, cementing its identification as an object in a distant galaxy.
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IC 348 south of Omicron Persei IC 348 is a star-forming region in the constellation Perseus located about 315 parsecs from the Sun. It consists of nebulosity and an associated 2-million-year-old cluster of roughly 400 stars within an angular diameter of 20″. The most massive stars in the cluster are the binary star system BD+31°643, which has a combined spectral class of B5. Based upon infrared observations using the Spitzer Space Telescope, about half of the stars in the cluster have a circumstellar disk, of which 60% are thick or primordial disks.
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NGC 2362, also known as Caldwell 64, is an open cluster of stars in the southern constellation of Canis Major. It was discovered by the Italian court astronomer Giovanni Batista Hodierna, who published his finding in 1654. William Herschel called it a "beautiful cluster", while William Henry Smyth said it "has a beautiful appearance, the bright white star being surrounded by a rich gathering of minute companions, in a slightly elongated form, and nearly vertical position". In the past it has also been listed as a nebula, but in 1930 Robert J. Trumpler found no evidence of nebulosity.
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A closer view of knots in the nebula The Helix Nebula was the first planetary nebula discovered to contain cometary knots. Its main ring contains knots of nebulosity, which have now been detected in several nearby planetary nebulae, especially those with a molecular envelope like the Ring nebula and the Dumbbell Nebula. These knots are radially symmetric (from the CS) and are described as "cometary", each centered on a core of neutral molecular gas and containing bright local photoionization fronts or cusps towards the central star and tails away from it. All tails extend away from the Planetary Nebula Nucleus (PNN) in a radial direction.
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The Keyhole Nebula is a dark nebulosity superimposed on the brightest part of the Carina Nebula. The Keyhole, or Keyhole Nebula, is a small dark cloud of cold molecules and dust within the Carina Nebula, containing bright filaments of hot, fluorescing gas, silhouetted against the much brighter background nebula. John Herschel used the term "lemniscate-oval vacuity" when first describing it, and subsequently referred to it simply as the "oval vacuity". The term lemniscate continued to be used to describe this portion of the nebula until popular astronomy writer Emma Converse described the shape of the nebula as "resembling a keyhole" in an 1873 Appleton's Journal article.
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RCW 88 is an emission nebula in the southern constellation of Circinus that first appeared in the 1960 astronomical catalogue by Rodgers, Campbell & Whiteoak (RCW) of Hα-emission regions within the southern Milky Way. Earlier observers, like James Wray in 1966, misclassified this as a likely 12.0v magnitude planetary nebula, but later spectroscopic investigations revealed this as a diffuse nebulae. RCW 88 was then to be identified by the infrared satellite IRAS as an HII region. Deep red images reveal that the inner nebula is divided into two parts by a central dark lane, and there is evidence of a larger halo of fainter nebulosity extending perhaps out to 10 arcmin.
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Crux with λ Centauri and its associated nebulosity visible at the top of the image Based upon the position and movement of this star through space, it is a likely member of the Gould Belt. In particular, it belongs to the Lower Centaurus-Crux (LCC) group of the Scorpius–Centaurus Association, which is the nearest OB association to the Sun. This is a loose grouping of stars that share a common motion through space and therefore formed in the same molecular cloud. The LCC group has an estimated age of 16–20 million years and is centered on a mean distance of from Earth.
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Sh2-155 (also designated Caldwell 9, Sharpless 155 or S155) is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. It is widely known as the Cave Nebula, though that name was applied earlier to Ced 201, a different nebula in Cepheus. Sh2-155 is an ionized H II region with ongoing star formation activity, at an estimated distance of 725 parsecs (2400 light-years) from Earth. Sh2-155 was first noted as a galactic emission nebula in 1959 in the extended second edition of the Sharpless catalogue, being a part of the much larger Cep OB3 Association.
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ESO/Digitized Sky Survey 2) HR 5171 appears near the centre of the HII Region Gum 48d, a ring of material ionised most likely by one or both of the visible HR 5171 stars. The stars and the nebulosity all show similar space motions that would place them in the Centaurus spiral arm about 4,000 parsecs (4 kpc) away from Earth. It is apparently part of an extensive molecular cloud complex with a distance between 3.2 kpc and 5.5 kpc from Earth. Gum 48d would require one or two O-type stars to be ionised, presumably one or both of the HR 5171 stars a few million years ago.
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Orion's Belt and nebulosity, including the Flame Nebula (left) and Horsehead Nebula (lower left) named after a relatively small dark cloud, rotated 90° somewhat resembling a seahorse Orion's Belt or the Belt of Orion, also known as the Three Kings or Three Sisters, is an asterism in the constellation Orion. It consists of the three bright stars Alnitak, Alnilam and Mintaka. Looking for Orion's Belt in the night sky is the easiest way to locate Orion in the sky. The stars are more or less evenly spaced in a straight line, and so can be visualized as the belt of the eponymous hunter's clothing.
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Perhaps the most striking feature is the rich FeII emission in both permitted and forbidden lines, with the forbidden lines arising from excitation of low density nebulosity around the star. The earliest analyses of the star's spectrum are descriptions of visual observations from 1869, of prominent emission lines "C, D, b, F, and the principal green nitrogen line". Absorption lines are explicitly described as not being visible. The letters refer to Fraunhofer's spectral notation and correspond to Hα, HeI, FeII, and Hβ. It is assumed that the final line is from FeII very close to the green nebulium line now known to be from OIII.
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Infrared image of the nebulosity around WR 102 () WR 102, of spectral classification WO2, is one of the very few known oxygen-sequence Wolf–Rayet stars, just four in the Milky Way galaxy and five in external galaxies. It is also the hottest known, with a surface temperature of 210,000 K. Modelling the atmosphere gives a luminosity around , while calculations from brightness and distance gives luminosity of with a distance of parsec. It is a very small dense star, with a radius around and a mass of . Very strong stellar winds with a terminal velocity of 5,000 kilometers per second are causing WR 102 to lose /year.
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Nebulosity around the B[e] star HD 87643 A B[e] star, frequently called a B[e]-type star, is a B-type star with distinctive forbidden neutral or low ionisation emission lines in its spectrum. The designation results from combining the spectral class B, the lowercase e denoting emission in the spectral classification system, and the surrounding square brackets signifying forbidden lines. These stars frequently also show strong hydrogen emission lines, but this feature is present in a variety of other stars and is not sufficient to classify a B[e] object. Other observational characteristics include optical linear polarization and often infrared radiation that is much stronger than in ordinary B-class stars, called infrared excess.
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Colin Stanley Gum (4 June 1924 – 29 April 1960) was an Australian astronomer who catalogued emission nebulae in the southern sky at the Mount Stromlo Observatory using wide field photography. Gum published his findings in 1955 in a study entitled A study of diffuse southern H-alpha nebulae which presented a catalog, now known as the Gum catalog, of 85 nebulae or nebular complexes. Gum 12, a huge area of nebulosity in the direction of the constellations Puppis and Vela, was later named the Gum Nebula in his honour. Gum was part of the team, whose number included Frank John Kerr and Gart Westerhout, that determined the precise position of the neutral hydrogen plane in space.
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It is sometimes claimed that Bayer could not have resolved the pair into two patches of nebulosity, and that Chi refers to the Double Cluster and h to a nearby star; see Stephen James O'Meara and Daniel W.E. Green, 2003, "The Mystery of the Double Cluster", Sky and Telescope, Vol. 105, No. 2 (February 2003), p. 116–119. Bayer's Uranometria chart for Perseus does not show them as nebulous objects, but his chart for Cassiopeia does, and they are described as Nebulosa Duplex in Schiller's Coelum Stellatum Christianum, which was assembled with Bayer's help; see Morton Wagman, Lost Stars, McDonald & Woodward, 2003, , p. 240. The cluster is most likely around 12.5 million years old.
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Radioactive molecules in the remains of a stellar collision. The luminosity of the central object, estimated from infrared dust emission, is about . The luminosity required to energise the observed nebulosity is calculated at from an object at 60,000 K At the time of its eruption, the luminosity of CK Vulpeculae is calculated to have been at least . Known ionic emission lines in the spectrum, and unidentified absorption features in the infrared indicate a temperature between 14,000 K and 100,000 K. Astronomers using the Atacama Large Millimetre Array (ALMA) and the Northern Extended Millimeter Array (NOEMA) radio telescopes to study CK Vulpeculae have found the first convincing evidence of radioactive debris outside the Earth's Solar System.
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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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The first certain observations of Jupiter's moons (I - IV) were those published by Galileo Galilei in 1610. No additional moons were discovered until E. E. Barnard observed Amalthea (Jupiter V) in 1892. Perrine participated in four solar eclipse expeditions of the Lick Observatory: 1900 (Georgia, USA), 1901 (Sumatra), 1905 (Spain), and 1908 (Flint Island), and was in charge of the one sent to Sumatra. Also in 1901, he and George Ritchey observed the apparent superluminal motion in the nebulosity surrounding Nova Persei 1901. In 1909 he resigned from the Lick Observatory to accept the position of Director of the Argentine National Observatory (today, Observatorio Astronómico de Córdoba) at Cordoba, Argentina from 1909 until his retirement in 1936 at age 69.
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Typical star densities in the centre of a cluster are about 1.5 stars per cubic light year; the stellar density near the Sun is about 0.003 stars per cubic light year. Open clusters are often classified according to a scheme developed by Robert Trumpler in 1930. The Trumpler scheme gives a cluster a three part designation, with a Roman numeral from I-IV indicating its concentration and detachment from the surrounding star field (from strongly to weakly concentrated), an Arabic numeral from 1 to 3 indicating the range in brightness of members (from small to large range), and p, m or r to indication whether the cluster is poor, medium or rich in stars. An 'n' is appended if the cluster lies within nebulosity.
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The first HH object was observed in the late 19th century by Sherburne Wesley Burnham, when he observed the star T Tauri with the refracting telescope at Lick Observatory and noted a small patch of nebulosity nearby. It was thought to be an emission nebula, later becoming known as Burnham's Nebula, and was not recognized as a distinct class of object. T Tauri was found to be a very young and variable star, and is the prototype of the class of similar objects known as T Tauri stars which have yet to reach a state of hydrostatic equilibrium between gravitational collapse and energy generation through nuclear fusion at their centres. Fifty years after Burnham's discovery, several similar nebulae were discovered with almost star-like appearance.
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Eta Carinae orbit The binary nature of Eta Carinae is clearly established, although the components have not been directly observed and cannot even be clearly resolved spectroscopically due to scattering and re-excitation in the surrounding nebulosity. Periodic photometric and spectroscopic variations prompted the search for a companion, and modelling of the colliding winds and partial "eclipses" of some spectroscopic features have constrained the possible orbits. The period of the orbit is accurately known at 5.539 years, although this has changed over time due to mass loss and accretion. The period between the Great Eruption and the smaller 1890 eruption was apparently 5.52 years, while before the Great Eruption it may have been lower still, possibly between 4.8 and 5.4 years.
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These two objects are generally identified today (as by the NGC/IC Project and Uranometria) with two brighter knots of nebulosity in a cloud at the northern edge of the loop, to the east of the northern edge of Pickering's Triangle. NGC 6979 was reported by William Herschel, and while the coordinates he recorded for Veil objects were somewhat imprecise, his position for this one is tolerably close to the knot at J2000 RA Dec . The identifier NGC 6979 is sometimes taken to refer to Pickering's Triangle,See, for example, this photo posted by Astronomy Magazine (accessed 2010-12-01). but the Triangle is probably not what Herschel saw or what the Catalogue intended for this entry: it was discovered only photographically, after the Catalogue was published, and long after Herschel's observation.
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IC 349, also known as Barnard's Merope Nebula, is a nebula which lies 3500 AUs (0.06 light years) from the star Merope in the Pleiades cluster. It was discovered in November 1890 by the American astronomer Edward Emerson Barnard, who described it as "a new and comparatively bright round cometary nebula close south and following Merope (23 Tau) ... about 30" in diameter, of the 13 (magnitude), gradually brighter in the middle, and very cometary in appearance.” The British astronomer Charles Pritchard, however, disputed Barnard's discovery announcement, claiming to have discovered it himself on a photographic plate obtained at Oxford on 29 January 1889. Pritchard dismissed IC 349 as an "apparently insignificant fleck," dismissing a distinct identity for the object and instead regarding it simply as the brightest part of the broader reflection nebulosity enveloping the Pleiades.
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The C cloud of the Vela Molecular Ridge is observed north of the easternmost part of the Gum Nebula, about 1000 parsecs away in the direction of the Gum 17 (RCW 33) nebula, which, however, might not be connected to the region of the Vela Molecular Ridge., citato in Galaxy Map - RCW 33.The evolutionary phase of this structure is slightly younger than that of the nearby VMR D and shows signs of a recent star formation activity; inside which have been discovered some infrared sources deeply nested in dense molecular clouds showing C18O emission. Three of them coincide with the same number of Class I young stellar objects of intermediate mass, ranging between 2 and 10 M⊙; in addition to 28 probable protostars of medium-small mass and five very compact young clusters immersed in dense nebulosity.
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Guillaume Le Gentil was born in Coutances and first intended to enter the church before turning to astronomy. He discovered what are now known as the Messier objects M32, M36 and M38, as well as the nebulosity in M8, and he was the first to catalogue the dark nebula sometimes known as Le Gentil 3 (in the constellation Cygnus). Le Gentil's drawing of the Orion Nebula. He was part of the international collaborative project organized by Mikhail Lomonosov to measure the distance to the Sun, by observing the transit of Venus at different points on the earth. Edmond Halley had suggested the idea, but it required careful measurements from different places on earth, and the project was launched with more than a hundred observers dispatched to different parts of the globe, for observing the transit coming up in 1761.
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A broad view of Cygnus loop/Veil nebula in ultraviolet The nebula was discovered on 5 September 1784 by William Herschel. He described the western end of the nebula as "Extended; passes thro' 52 Cygni... near 2 degree in length", and described the eastern end as "Branching nebulosity... The following part divides into several streams uniting again towards the south." When finely resolved, some parts of the nebula appear to be rope-like filaments. The standard explanation is that the shock waves are so thin, less than one part in 50,000 of the radius, that the shell is visible only when viewed exactly edge-on, giving the shell the appearance of a filament. At the estimated distance of 2400 light-years, the nebula has a radius of 65 light- years (a diameter of 130 light-years). The thickness of each filament is 1/50,000th of the radius, or about 4 billion miles, roughly the distance from Earth to Pluto.
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V605 Aquilae, in the constellation Aquila, is the variable central star of the planetary nebula Abell 58. It is a highly unusual hydrogen-deficient carbon- rich star. V605 Aquilae was first recorded as a nova in 1919, but it turned out to be a very unusual variable. It was measured to be magnitude 10.4 at its peak. Investigation of prior photographs showed that it was magnitude 15 or fainter until 1918, when it brightened to 12th magnitude. It stayed at 11th magnitude or brighter for over a year, before fading from sight. It then brightened to 12th magnitude in late 1921 and again in 1923, before disappearing. The spectral type at the time of the outbursts was R0, a cool hydrogen-deficient carbon star similar to some R Coronae Borealis (RCB) stars. V605 Aquilae was subsequently detected several times at magnitudes 18–20, but these are likely to have been detections only of a small knot of nebulosity surrounding the position of the star.
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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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