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Supernova Impostor
Supernova impostors are stellar explosions that appear at first to be a supernova but do not destroy their progenitor stars. As such, they are a class of extra-powerful novae. They are also known as Type V supernovae, Eta Carinae analogs, and giant eruptions of luminous blue variables (LBV). Appearance, origin and mass loss Supernova impostors appear as remarkably faint supernovae of spectral type IIn—which have hydrogen in their spectrum and narrow spectral lines that indicate relatively low gas speeds. These impostors exceed their pre-outburst states by several magnitudes, with typical peak absolute visual magnitudes of −11 to −14, making these outbursts as bright as the most luminous stars. The trigger mechanism of these outbursts remains unexplained, though it is thought to be caused by violating the classical Eddington luminosity limit, initiating severe mass loss. If the ratio of radiated energy to kinetic energy is near unity, as in Eta Carinae, then we might e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2010dn-NGC3184-2010Jun01
1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sports, where it commonly denotes the first, leading, or top thing in a group. 1 is the unit of counting or measurement, a determiner for singular nouns, and a gender-neutral pronoun. Historically, the representation of 1 evolved from ancient Sumerian and Babylonian symbols to the modern Arabic numeral. In mathematics, 1 is the multiplicative identity, meaning that any number multiplied by 1 equals the same number. 1 is by convention not considered a prime number. In digital technology, 1 represents the "on" state in binary code, the foundation of computing. Philosophically, 1 symbolizes the ultimate reality or source of existence in various traditions. In mathematics The number 1 is the first natural number after 0. Each natural number, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 2403
NGC 2403 (also known as Caldwell 7) is an intermediate spiral galaxy in the constellation Camelopardalis. It is an outlying member of the M81 Group, and is approximately 8 million light-years distant. It bears a similarity to Messier 33, M33, containing numerous star-forming H II regions, but being a little bit larger at approximately 90,000 light-years in diameter compared to the 61,100 light-year diameter of M33. The northern spiral arm connects it to the star forming region NGC 2404. NGC 2403 can be observed using 10×50 binoculars. NGC 2404 is 940 light-years in diameter, making it one of the largest known H II regions. This H II region represents striking similarity with NGC 604 in M33, both in size and location in galaxy. Supernovae and Supernovae Imposters There have been four reported Time-domain astronomy, astronomical transients in the galaxy: * SN 1954J was first noticed by Gustav_Andreas_Tammann, Gustav Tammann and Allan Sandage as a "bright blue irregular variable" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Failed Supernova
A failed supernova is an astronomical event in time domain astronomy in which a star suddenly brightens as in the early stage of a supernova, but then does not increase to the massive flux of a supernova. They could be counted as a subcategory of supernova imposters. They have sometimes misleadingly been called unnovae. Overview Failed supernovae are thought to create stellar black holes by the collapsing of a red supergiant star in the early stages of a supernova. When the star can no longer support itself, the core collapses completely, forming a stellar-mass black hole, and consuming the nascent supernova without having the massive explosion. For a distant observer, the red supergiant star will seem to wink out of existence with little or no flare-up. The observed instances of these disappearances seem to involve supergiant stars with masses above 17 solar masses. Failed supernovae are one of several events that theoretically signal the advent of a black hole born from an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN 2006jc
SN 2006jc was a Type_Ib_and_Ic_supernovae, typeIbn supernova that was detected on October 9, 2006 in the galaxy UGC 4904, which is about 77 million light-years away in the constellation Lynx constellation, Lynx. It was first seen by Japanese amateur astronomer Kōichi Itagaki, American amateur Tim Puckett, and Italian amateur Roberto Gorelli. Two years earlier, on 20 October 2004, the Supernova#Progenitor, progenitor star produced a supernova impostor that was detected by Itagaki. This outburst was apparently the progenitor star shedding its outer layers. When the star exploded in 2006, the shockwave hit the material blown off in 2004, heating it to millions of degrees and emitting copious amounts of X-rays. References External links Light curves and spectra on thOpen Supernova Catalog {{supernovae Supernovae Lynx (constellation) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kōichi Itagaki
is an amateur astronomer based in Yamagata, the capital city of Yamagata Prefecture in the Tōhoku region of northern Honshu island, Japan. He is responsible for discovering many comets, and over 170 supernovae.The Starwatcher: Amateur astronomer Koichi Itagaki is one of the most prolific supernova hunters of all time Dennis Normile, , 2023-07-06 Early life Itagaki had an early fascination with es, and used them to ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UGC 4904
UGC 4904 is a barred spiral galaxy in the constellation Lynx. Its velocity with respect to the cosmic microwave background is 1880 ± 15km/s, which corresponds to a Hubble distance of . The first known reference to this galaxy comes from Part 2 of the Morphological Catalogue of Galaxies, published in 1964, where it is listed as MCG +07-19-054. Supernova On October 20, 2004, a supernova impostor was observed by Japanese amateur astronomer Kōichi Itagaki within the galaxy. This same star may have transitioned from a luminous blue variable star to a Wolf–Rayet star shortly before it was observed as blowing up as supernova SN 2006jc ( typeIbn, mag. 13.8) on October 11, 2006. References External links UGC 4904in a SIMBAD SIMBAD (the Set of Identifications, Measurements and Bibliography for Astronomical Data) is an astronomy, astronomical database of objects beyond the Solar System. It is maintained by the Centre de données astronomiques de Strasbourg (CDS), Fr ... U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 3184
NGC 3184, the Little Pinwheel Galaxy, is an unbarred spiral galaxy approximately 40 million light-years away in the constellation Ursa Major. Its name comes from its resemblance to the Pinwheel Galaxy. It was discovered on 18 March 1787 by German-British astronomer William Herschel. It has two HII regions named NGC 3180 and NGC 3181. NGC 3184 houses a high abundance of heavy elements. The blue color of its spiral arms comes mostly from relatively few bright young blue stars. The bright stars that highlight the arms were created in huge density waves that circle the center. Structure NGC 3184 has two prominent spiral arms. They have constant pitch angles, which makes them both symmetrical. Supernovae and Astronomical Transients Seven supernovae and astronomical transients have been observed in NGC 3184: * SN 1921B (type unknown, mag. 13.5) was discovered by Fritz Zwicky on 6 April 1921. * SN 1921C (type unknown, mag. 11) was discovered on 5 December 1921. * SN 1937F (type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6946
NGC 6946, sometimes referred to as the Fireworks Galaxy, is a grand design, face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 (NGC 5457) in the constellation Ursa Major. Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster. The galaxy was discovered by William Herschel on 9 September 1798. Based on an estimation by the Third Reference Catalogue of Bright Galaxies (RC3) in 1991, the galaxy has a D25 B-band isophotal diameter of . It is heavily obscured by interstellar matter due to its location close to the galactic plane of the Milky Way. Due to its prodigious sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN 1997bs
SN 1997bs was a subluminous type II supernova that occurred in the intermediate spiral galaxy Messier 66, about 31 million light years from Earth, in April of 1997. The progenitor star that produced this supernova was a massive luminous blue variable that was similar to the star Eta Carinae. This star was not associated with an H II region or any nearby massive stars. It is possible that the star that produced SN 1997bs survived the explosion and is hidden in a thick shell of dust with a mass of around 1 solar mass. SN 1997bs was the first supernova discovered by the Lick Observatory Supernova Search The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton (California), Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The ... (LOSS). References Supernovae Leo (constellation) {{star-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN 1961V
SN 1961V was an abnormal, supernova-like event that was a potential supernova impostor. It was discovered by Paul Wild on 11 July 1961. The potential impostor nature of SN 1961V was first identified by Fritz Zwicky in 1964. SN 1961V occurred in galaxy NGC 1058, about 9.3 Mpc away (about 30 million light years). Unlike many supernovae, the progenitor star is tentatively known: an extremely large, very bright blue star, similar to Eta Carinae. Mass estimates of the precursor star were as high as 2000 times the mass of the sun, but these are likely to be extreme overestimates. If SN 1961V was not a supernova then it was most likely an extremely large outburst by a luminous blue variable star. The remnant of SN 1961V's explosion is expanding at 2,000 km/s, which is much slower than the majority of supernovae. The profile of its light curve, with a gradual climb to maximum brightness, was unusual when compared to a supernova. This unusual light curve led to suspicion that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernova
A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the ''progenitor'', either collapses to a neutron star or black hole, or is completely destroyed to form a diffuse nebula. The peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months. The last supernova directly observed in the Milky Way was Kepler's Supernova in 1604, appearing not long after Tycho's Supernova in 1572, both of which were visible to the naked eye. The supernova remnant, remnants of more recent supernovae have been found, and observations of supernovae in other galaxies suggest they occur in the Milky Way on average about three times every century. A supernova in the Milky Way would almost certainly be observable through mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P Cygni
P Cygni (34 Cygni) is a variable star in the constellation Cygnus. The designation "P" was originally assigned by Johann Bayer in '' Uranometria'' as a nova. Located about 5,300 light-years (1,560 parsecs) from Earth, it is a hypergiant luminous blue variable (LBV) star of spectral type B1-2 Ia-0ep that is one of the most luminous stars in the Milky Way. Visibility The star is located about 5,000 to 6,000 light-years (1,500–1,800 parsecs) from Earth. Despite this vast distance, it is visible to the naked eye in suitable dark sky locations. It was unknown until the end of the 16th century, when it suddenly brightened to 3rd magnitude. It was first observed on 18 August (Gregorian) 1600 by Willem Janszoon Blaeu, a Dutch astronomer, mathematician and globe-maker. Bayer's atlas of 1603 assigned it the miscellaneous label P and the name has stuck ever since. After six years the star faded slowly, dropping below naked-eye visibility in 1626. It brightened again in 1655, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
