A supernova is a powerful and luminous explosion of a star. A supernova occurs during the last 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.
SN 1987A was a type II supernova in the Large Magellanic Cloud, a dwarf satellite galaxy of the Milky Way. It occurred approximately 51.4 kiloparsecs from Earth and was the closest observed supernova since Kepler's Supernova in 1604. Light and neutrinos from the explosion reached Earth on February 23, 1987 and was designated "SN 1987A" as the first supernova discovered that year. Its brightness peaked in May of that year, with an apparent magnitude of about 3.
Timeline of neutron stars, pulsars, supernovae, and white dwarfs
Messier 66 or M66, also known as NGC 3627, is an intermediate spiral galaxy in the southern, equatorial half of Leo. It was discovered by French astronomer Charles Messier on 1 March 1780, who described it as "very long and very faint". This galaxy is a member of a small group of galaxies that includes M65 and NGC 3628, known as the Leo Triplet or the M66 Group. M65 and M66 are a common object for amateur astronomic observation, being separated by only 20′.
3C 58 or 3C58 is a pulsar and supernova remnant within the Milky Way. The object is listed as No. 58 in the Third Cambridge Catalogue of Radio Sources.
First observed between August 4 and August 6, 1181, Chinese and Japanese astronomers recorded the supernova now known as SN 1181 in eight separate texts. One of only five supernovae in the Milky Way confidently identified in pre-telescopic records, it appeared in the constellation Cassiopeia and was visible and motionless against the fixed stars for 185 days. F. R. Stephenson first recognized that the 1181 AD "guest star" must be a supernova, because such a bright transient that lasts for 185 days and does not move in the sky can only be a galactic supernova.
SN 1006 was a supernova that is likely the brightest observed stellar event in recorded history, reaching an estimated −7.5 visual magnitude, and exceeding roughly sixteen times the brightness of Venus. Appearing between April 30 and May 1, 1006, in the constellation of Lupus, this "guest star" was described by observers across China, Japan, modern-day Iraq, Egypt, and Europe, and was possibly recorded in North American petroglyphs. Some reports state it was clearly visible in the daytime. Modern astronomers now consider its distance from Earth to be about 7,200 light-years or 2,200 parsecs.
A Type Ia supernova is a type of supernova that occurs in binary systems in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf.
NGC 6744 is an intermediate spiral galaxy in the constellation Pavo (Peacock). Its velocity with respect to the cosmic microwave background is 802 ± 3 km/s, which corresponds to a Hubble distance of 38.6 ± 2.7 Mly (11.82 ± 0.83 Mpc). However, 21 non redshift measurements give a distance of 23.63 ± 1.68 Mly (7.244 ± 0.514 Mpc). It was discovered on 30 June 1826 by Scottish astronomer James Dunlop, observing from Parramatta, Australia.
NGC 1309 is a spiral galaxy located approximately 120 million light-years away, appearing in the constellation Eridanus. It was discovered by German-British astronomer William Herschel on 3 October 1785.
The known history of supernova observation goes back to 1006 AD. All earlier proposals for supernova observations are speculations with many alternatives.
NGC 1808 is a barred spiral galaxy located in the southern constellation of Columba, about two degrees to the south and east of Gamma Caeli. It was discovered on 10 May 1826 by Scottish astronomer James Dunlop, who described it as a "faint nebula". The galaxy is a member of the NGC 1808 group, which is part of the larger Dorado Group.
SN 2011fe, initially designated PTF 11kly, was a Type Ia supernova discovered by the Palomar Transient Factory (PTF) survey on 24 August 2011 during an automated review of images of the Messier 101 from the nights of 22 and 23 August 2011. It was located in Messier 101, the Pinwheel Galaxy, 21 million light years from Earth. It was observed by the PTF survey very near the beginning of its supernova event, when it was approximately 1 million times too dim to be visible to the naked eye. It is the youngest type Ia ever discovered. About 13 September 2011, it reached its maximum brightness of apparent magnitude +9.9 which equals an absolute magnitude of about -19, equal to 2.5 billion Suns. At +10 apparent magnitude around 5 September, SN 2011fe was visible in small telescopes. As of 30 September the supernova was at +11 apparent magnitude in the early evening sky after sunset above the northwest horizon. It had dropped to +13.7 as of 26 November 2011.
SN 1895B was a supernova event in the irregular dwarf galaxy NGC 5253, positioned 16″ east and 23″ north of the galactic center. It is among the closest known extragalactic supernova events. The supernova was discovered by Williamina Fleming on December 12, 1895 after noticing an unusual spectrum on a photographic plate taken July 18, 1895, and was initially given the variable star designation Z Centauri. The light curve is consistent with an event that began ~15 days before the discovery plate was taken, and this indicates the supernova reached a peak visual magnitude of up to 8.49±0.03.
In astronomy, a calcium-rich supernova is a subclass of supernovae that, in contrast to more well-known traditional supernova classes, are fainter and produce unusually large amounts of calcium. Since their luminosity is located in a gap between that of novae and other supernovae, they are also referred to as "gap" transients. Only around 15 events have been classified as a calcium-rich supernova – a combination of their intrinsic rarity and low luminosity make new discoveries and their subsequent study difficult. This makes calcium-rich supernovae one of the most mysterious supernova subclasses currently known.
NGC 1084 is an unbarred spiral galaxy in the constellation Eridanus. It is located at a distance of about 63 million light-years away from the Milky Way. The galaxy was discovered by William Herschel on 10 January 1785. It has multiple spiral arms, which are not well defined. It belongs in the same galaxy group with NGC 988, NGC 991, NGC 1022, NGC 1035, NGC 1042, NGC 1047, NGC 1052 and NGC 1110. This group is in turn associated with the Messier 77 group.
iPTF14hls is an unusual supernova star that erupted continuously for about 1,000 days beginning in September 2014 before becoming a remnant nebula. It had previously erupted in 1954. None of the theories nor proposed hypotheses fully explain all the aspects of the object.
IRAS 00500+6713 is the catalogued infrared source for an unusual nebula in Cassiopeia, while the central star has a designation WD J005311, with the whole system designated as Pa 30. The central star and its surrounding shell were created by the supernova seen in the year 1181 as reported by Chinese and Japanese observers. Both the nebula and central star have unique and extreme properties, pointing to their creation by a rare type Iax supernova, where two ultra-dense white dwarfs in-spiral to a collision and explosion.
SN 2020oi was a supernova event in the grand design spiral galaxy known as Messier 100, or NGC 4321. It was discovered January 7, 2020 at an apparent magnitude of 17.28 by F. Forster and associates using the Zwicky Transient Facility. The position places it ~4.67″ north of the galactic nucleus. The supernova was not detected on an observation made three days before the discovery, and thus it must have begun during that brief period. The light curve peaked around January 13–18, depending on the wavelength, then declined rapidly over a period of 25 days before flattening into a more gradual decline. Observations of the spectrum made with the SOAR telescope showed this to be a type Ic supernova, with the progenitor being a massive star that had its outer envelope stripped. The initial velocity of the expanding photosphere was ~15,000 km/s.
