The Eskimo Nebula (NGC 2392), also known as the Clown-faced Nebula, Lion Nebula,[4] or Caldwell 39, is a bipolar[5] double-shell[6]planetary nebula (PN). It was discovered by astronomer William Herschel in 1787. The formation resembles a person's head surrounded by a parka hood. It is surrounded by gas that composed the outer layers of a Sun-like star. The visible inner filaments are ejected by a strong wind of particles from the central star. The outer disk contains unusual, light-year-long filaments.
NGC 2392 lies about 6500 light-years away, and is visible with a small telescope in the constellation of Gemini.
At the center of NGC 2392, there is an O-type star with a spectral type of O(H)6f.[7]
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."[8] NGC 2392 WH IV-45 is included in the Astronomical League's Herschel 400 observing program.
On 11 August 2020, the IAU Working Group on Star Names (WGSN),[citation needed] NASA/IPAC Extragalactic Database (NED),[citation needed] and SIMBAD Astronomical Database (CDS) discontinued use of three nicknames that were perceived as offensive - "Eskimo Nebula", "Clown Face Nebula", and "Clownface Nebula" - and strongly recommended the nebula be referred to by its NGC designation in further publications.[9][1]
↑O'Dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J. et al. (2002). "Knots in Nearby Planetary Nebulae". The Astronomical Journal123 (6): 3329–3347. doi:10.1086/340726. Bibcode: 2002AJ....123.3329O.
↑Deep-Sky Companions: The Caldwell Objects, 2nd Edition, Stephen James O'Meara, 2016, p.181
↑O'dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; Burkert, A. (2003). "Knots in Planetary Nebulae". in S. J. Arthur & W. J. Henney. Winds, Bubbles, and Explosions: a conference to honor John Dyson, Pátzcuaro, Michoacán, México, September 9–13, 2002. 15. pp. 29–33. Bibcode: 2003RMxAC..15...29O. http://www.astroscu.unam.mx/~rmaa/. Retrieved 2007-01-04.
↑Guerrero, M. A.; Chu, Y.-H.; Gruendl, R. A.; Meixner, M. (2005). "XMM-Newton detection of hot gas in the Eskimo Nebula: Shocked stellar wind or collimated outflows?". Astronomy and Astrophysics430 (3): L69–L72. doi:10.1051/0004-6361:200400131. Bibcode: 2005A&A...430L..69G.
↑González-Santamaría, I.; Manteiga, M.; Manchado, A.; Ulla, A.; Dafonte, C.; López Varela, P. (2021). "Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity". Astronomy & Astrophysics656: A51. doi:10.1051/0004-6361/202141916. Bibcode: 2021A&A...656A..51G.
↑The Scientific Papers of Sir William Herschel by J. L. E. Dreyer, Royal Society, London 1912