Eskimo Nebula

Eskimo Nebula
NGC 2392, the Eskimo Nebula by HST. Credit: NASA/ESA/STScI
Observation data (Epoch J2000)
Right ascension	07h 29m 10.7669s[1]
Declination	+20° 54′ 42.488″[1]
Distance	≥2,870 ly (≥880 pc)[2]
Apparent magnitude (V)	10.1[1]
Apparent dimensions (V)	48″ × 48″[3]
Constellation	Gemini
Physical characteristics
Radius	≥0.34 ly[a]
Absolute magnitude (V)	≤0.4 [b]
Notable features	–
Other designations	NGC 2392,[1] Caldwell 39, Clown Nebula,[1] Clown Face[1]
See also: Planetary nebula, Lists of nebulae

The Eskimo Nebula (NGC 2392), also known as the Clownface Nebula^[4] or Caldwell 39, is a bipolar^[2] double-shell^[5] 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 strong wind of particles from the central star. The outer disk contains unusual light-year long orange filaments.

NGC 2392 lies more than 2,870 light-years away and is visible with a small telescope in the constellation of Gemini.

Historic data

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."^[6] NGC 2392 WH IV-45 is included in the Astronomical League's Herschel 400 observing program.

See also

• List of planetary nebulae
• New General Catalogue

Notes

1. ^{^} Radius = distance × sin(angular size / 2) = ≥2900 ly * sin(48″ / 2) = ≥0.34 ly
2. ^{^} 10.1 apparent magnitude - 5 * (log₁₀(≥880 pc distance) - 1) = ≤0.4 absolute magnitude

References

1. ^ ^{a b c d e f} "SIMBAD Astronomical Database". Results for Eskimo Nebula. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+2392. Retrieved 2006-12-22. 
2. ^ ^{a b} O'dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; Burkert, A. (2003). "Knots in Planetary Nebulae". Winds, Bubbles, and Explosions: a conference to honor John Dyson, Pátzcuaro, Michoacán, México, September 9–13, 2002 (Eds. S. J. Arthur & W. J. Henney) Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias) (http://www.astroscu.unam.mx/~rmaa/) 15: 29–33. Bibcode 2003RMxAC..15...29O. 
3. ^ O'Dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; Burkert, A. (2002). "Knots in Nearby Planetary Nebulae". The Astronomical Journal 123 (6): 3329–3347. Bibcode 2002AJ....123.3329O. doi:10.1086/340726. 
4. ^ Windows to the Universe
5. ^ 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 Astrophysics 430 (3): L69–L72. arXiv:astro-ph/0412540. Bibcode 2005A&A...430L..69G. doi:10.1051/0004-6361:200400131. 
6. ^ The Scientific Papers of Sir William Herschel by J. L. E. Dreyer, Royal Society, London 1912

External links

• APOD (2003-12-07) – NGC 2392: The Eskimo Nebula
• The Eskimo Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Coordinates: 07^h 29^m 10.7669^s, +20° 54′ 42.488″