The Eskimo Nebula is a bipolar,[5] double-shell[6]planetary nebula (PN) in the northern constellation of Gemini. Alternatively, it is known as NGC 2392, Clown Face Nebula, Lion Nebula,[7] or Caldwell 39. This feature was discovered by German-British astronomerWilliam Herschel in 1787. NGC 2392 lies about 6,500 light-years away, and is visible with a small telescope. The formation resembles a person's head surrounded by a parka hood. It is surrounded by gas that composed the ejected outer layers of a Sun-like star. The visible inner filaments are ejected by a strong wind of particles from the central stellar remnant. The outer disk contains unusual, light-year-long filaments.
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."[10] NGC 2392 WH IV-45 is included in the Astronomical League's Herschel 400 observing program.
On 9 January 1982 it was occulted by the Moon during a Total Lunar Eclipse (the January 1982 lunar eclipse) over Greenland, the Arctic, the extreme northeast of North America, the northern half of Europe, North and Northeast Asia. This event was seen by several observers in England. The occultation during total eclipse will happen again during the January 2066 lunar eclipse over the northern half of Asia and the Northwest Pacific.[11]: 158
A true color image of NGC 2392.
A wider field of view of NGC 2392
An optical and microwave composite image of NGC 2392
An optical (Hubble Space Telescope) and X-Ray (Chandra) composite image of NGC 2392.
Naming controversy
Location of Eskimo Nebula in Gemini, just east of δ Geminorum (annotated as 2392)
On 11 August 2020, the IAU Working Group on Star Names (WGSN), NASA/IPAC Extragalactic Database (NED),{{citation needed|date=August 2020} ]] (CDS) discontinued use of nicknames that were perceived as offensive which included "Eskimo Nebula", and strongly recommended the nebula be referred to by its NGC designation in further publications.[12][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.
↑O'dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; Burkert, A. (2003). "Knots in Planetary Nebulae". in Arthur, S. J.; Henney, W. J.. 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.
↑O'Meara, Stephen James (2016). Deep-Sky Companions: The Caldwell Objects (2nd ed.). p. 181.