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Eskimo Nebula

Coordinates: Sky map 07h 29m 10.7669s, +20° 54′ 42.488″
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NGC 2392
Emission nebula
Planetary nebula
NGC 2392, the Eskimo Nebula by HST in 1999.
Observation data: J2000 epoch
Right ascension07h 29m 10.7669s[1]
Declination+20° 54′ 42.488″[1]
Distance6520±560[2] ly
Apparent magnitude (V)10.1[1]
Apparent dimensions (V)48″; × 48″;[3]
ConstellationGemini
Physical characteristics
Radius≥0.34 ly[a] ly
Absolute magnitude (V)≤0.4[b]
Notable features–
DesignationsNGC 2392,[1] Caldwell 39, PN G197.8+17.3
Central Star: HIP 36369, HD 59088, TYC 1372-1287-1
See also: Lists of nebulae

The Eskimo Nebula (NGC 2392), also known as the Clown Face 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 (designated HD 59088[7]) with a spectral type of O(H)6f.[8]

Historic data

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Full color ground-based image of NGC2392. Processed by Adam Block (astrophotographer).

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."[9] 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.[10]: 158 

Naming controversy

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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),[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.[11][1]

See also

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Notes

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  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

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  1. ^ a b c d e "NGC 2392". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-12-22.
  2. ^ Gaia Collaboration et al. (2018b): Summary of the contents and survey properties
  3. ^ O'Dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; et al. (2002). "Knots in Nearby Planetary Nebulae". The Astronomical Journal. 123 (6): 3329–3347. Bibcode:2002AJ....123.3329O. doi:10.1086/340726.
  4. ^ Deep-Sky Companions: The Caldwell Objects, 2nd Edition, Stephen James O'Meara, 2016, p.181
  5. ^ O'dell, C. R.; Balick, B.; Hajian, A. R.; Henney, W. J.; et al. (2003). "Knots in Planetary Nebulae". In S. J. Arthur & W. J. Henney (ed.). Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias). Winds, Bubbles, and Explosions: a conference to honor John Dyson, Pátzcuaro, Michoacán, México, September 9–13, 2002. Vol. 15. pp. 29–33. Bibcode:2003RMxAC..15...29O. Archived from the original on 2018-05-01. Retrieved 2007-01-04.
  6. ^ 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. S2CID 6518963.
  7. ^ Handler, G. (2 January 1996). "Three New Variable Planetary Nebula Central Stars: M 2-54, M 4-18 and NGC 2392". Information Bulletin on Variable Stars (4283). Konkoly Observatory, Budapest: International Astronomical Union. Bibcode:1996IBVS.4283....1H.
  8. ^ 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 & Astrophysics. 656: A51. arXiv:2109.12114. Bibcode:2021A&A...656A..51G. doi:10.1051/0004-6361/202141916. S2CID 237940344.
  9. ^ The Scientific Papers of Sir William Herschel by J. L. E. Dreyer, Royal Society, London 1912
  10. ^ Meeus, Jan (2002). "Occultations of deep-sky objects during a total lunar eclipse". More Mathematical Astronomy Morsels (PDF). pp. 157–162. ISBN 0943396743.
  11. ^ Talbert, Tricia (11 August 2020). "NASA to Reexamine Nicknames for Cosmic Objects". NASA. Retrieved 11 August 2020.
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