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NGC 4902
NGC 4902 is a barred spiral galaxy in the constellation Virgo (constellation), Virgo. The galaxy lies about 110 million light years away from Earth, which means, given its apparent dimensions, that NGC 4902 is approximately 100,000 light years across. It was discovered by William Herschel on February 8, 1785. Characteristics NGC 4902 has a prominent bar. There is a brighter stellar feature visible on the southwest side of the bar, but it could also be superimposed. Two spiral arms emerge at the ends of the bar and overlap, forming an inner ring.Sandage, A., Bedke, J. (1994), ''The Carnegie Atlas of Galaxies. Volume I'', Carnegie Institution of Washington There is a kink at the north side of the ring. Three spiral arms emanate from the ring, along with a fainter arm. The third arm appears semi-detacted from the inner ring. The arms are diffuse and feature many HII regions. The star formation rate of the galaxy is estimated to be 3.8 per year. Supernovae Three 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 galaxy, 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 Herschel, William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the Celestial sphere, 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 Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
