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NGC 5806
NGC 5806 is an intermediate spiral galaxy in the constellation Virgo (constellation), Virgo. It was discovered on February 24, 1786, by the astronomer John Herschel. It is located about 70 million light-years (or about 21 Megaparsecs) away from the Milky Way. It is a member of the NGC 5846 Group. 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 . NGC 5806 has also hosted several true supernovae. SN 2004dg (type II supernova, type II, mag. 17.1) was around 100 times brighter than SN Hunt 248. The progenitor of SN 2004dg has not been detected and is expected to have been a relatively low mass, low luminosity, red supergiant. The other supernovae are SN 2012P (type IIb, mag. 15) and iPTF13bvn (Type_Ib_and_Ic_supernovae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
