View source for Eskimo Nebula

{{short description|Planetary nebula in the constellation Gemini}}

{{ Planetary nebula
| image = [[File:Ngc2392.jpg|250px]]
| caption = NGC 2392, the Eskimo Nebula by [[Hubble Space Telescope|HST]] in 1999.
| credit = [[NASA]]/[[ESA]]/[[STScI]]
| name = NGC 2392
| type = Planetary
| epoch = [[J2000]]
| ra = {{RA|07|29|10.7669}}<ref name="simbad">{{cite simbad
  | title=NGC 2392
  | access-date=2006-12-22}}</ref>
| dec = {{DEC|+20|54|42.488}}<ref name="simbad" />
| dist_ly=6520±560<ref>[[Star catalogue#Gaia Catalogue|Gaia Collaboration et al.]] (2018b): [http://gea.esac.esa.int/archive/documentation/GDR2/bib.html#bib15 Summary of the contents and survey properties]</ref>
| appmag_v = 10.1<ref name="simbad" />
| size_v = 48{{pprime}}; × 48{{pprime}};<ref name="ODelletal2002">{{cite journal |
  author=O'Dell, C. R. |display-authors=4 | author2=Balick, B. | author3=Hajian, A. R. | author4=Henney, W. J. | author5=Burkert, A.
  | title=Knots in Nearby Planetary Nebulae
  | journal=The Astronomical Journal
  | date=2002
  | volume=123
  | issue=6
  | pages=3329–3347
  | bibcode=2002AJ....123.3329O
    | doi=10.1086/340726
| doi-access=free}}</ref>
| constellation = [[Gemini (constellation)|Gemini]]
| radius_ly = ≥0.34 ly{{Ref label|A|a|none}}
| absmag_v = ≤0.4{{Ref label|B|b|none}}
| notes = –
| names = [[New General Catalogue|NGC]] 2392,<ref name="simbad" /> [[Caldwell catalogue|Caldwell]] 39, PN G197.8+17.3<br />[[Planetary nebula#Central stars|Central Star]]: [[Hipparcos#Published catalogues|HIP]] 36369, HD 59088, [[Tycho-2 Catalogue|TYC]] 1372-1287-1
}}

The '''Eskimo Nebula''' ('''NGC 2392'''), also known as the '''Clown Face Nebula''', '''Lion Nebula''',<ref>Deep-Sky Companions: The Caldwell Objects, 2nd Edition, Stephen James O'Meara, 2016, p.181</ref> or '''Caldwell 39''', is a [[bipolar nebula|bipolar]]<ref name="ODelletal2003">{{cite conference | author=O'dell, C. R. | display-authors=4 | author2=Balick, B. | author3=Hajian, A. R. | author4=Henney, W. J. | author5=Burkert, A. | title=Knots in Planetary Nebulae | conference=Winds, Bubbles, and Explosions: a conference to honor John Dyson, Pátzcuaro, Michoacán, México, September 9–13, 2002 | editor=S. J. Arthur & W. J. Henney | book-title=[[Revista Mexicana de Astronomía y Astrofísica]] (Serie de Conferencias) | url=http://www.astroscu.unam.mx/~rmaa/ | date=2003 | volume=15 | pages=29–33 | bibcode=2003RMxAC..15...29O | access-date=2007-01-04 | archive-date=2018-05-01 | archive-url=https://web.archive.org/web/20180501131545/http://www.astroscu.unam.mx/~rmaa/ | url-status=dead }}</ref> double-shell<ref name="Guerreroetal2005">{{cite journal
  | author=Guerrero, M. A. | author2=Chu, Y.-H. | author3=Gruendl, R. A. | author4=Meixner, M.
  | title=XMM-Newton detection of hot gas in the Eskimo Nebula: Shocked stellar wind or collimated outflows?
  | journal=[[Astronomy and Astrophysics]]
  | date=2005
  | volume=430
  | issue=3
  | pages=L69–L72
  | bibcode=2005A&A...430L..69G
  | doi=10.1051/0004-6361:200400131
| arxiv = astro-ph/0412540 | s2cid=6518963 }}</ref> [[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 (constellation)|Gemini]].

At the center of NGC 2392, there is an [[O-type star]] (designated [[Henry Draper Catalogue|HD]] 59088<ref>{{cite journal|bibcode=1996IBVS.4283....1H|date=2 January 1996|title=Three New Variable Planetary Nebula Central Stars: M 2-54, M 4-18 and NGC 2392|last=Handler|first=G.|journal=Information Bulletin on Variable Stars|volume=4283 |issue=4283|page=1 |publisher=[[International Astronomical Union]]|location=[[Konkoly Observatory]], [[Budapest]]}}</ref>) with a [[spectral type]] of O(H)6f.<ref>{{cite journal|doi=10.1051/0004-6361/202141916|title=Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity|year=2021|last1=González-Santamaría|first1=I.|last2=Manteiga|first2=M.|last3=Manchado|first3=A.|last4=Ulla|first4=A.|last5=Dafonte|first5=C.|last6=López Varela|first6=P.|journal=Astronomy & Astrophysics|volume=656|pages=A51|arxiv=2109.12114|bibcode=2021A&A...656A..51G|s2cid=237940344}}</ref>

== 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."<ref>''The Scientific Papers of Sir William Herschel'' by [[J. L. E. Dreyer]], Royal Society, London 1912</ref> 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 Asia|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]].<ref name="Mus2002">{{cite book |date=2002 |first=Jan |last=Meeus |chapter=Occultations of deep-sky objects during a total lunar eclipse |pages=157–162 |title=More Mathematical Astronomy Morsels |publisher=Willmann-Bell |isbn=0943396743 |url=https://falakmu.id/khgt/dokumen/More%20mathematical%20astronomy%20morsels%20(Jean%20Meeus)%20(Z-Library).pdf}}</ref>{{rp|158}}
{{clear|left}}

== Naming controversy ==
[[File:Gemini IAU.svg|left|thumb|Location of Eskimo Nebula in Gemini, just east of [[Delta Geminorum|δ Geminorum]] (annotated as 2392)]]

On 11 August 2020, the [[IAU Working Group on Star Names]] (WGSN),{{citation needed|date=August 2020}} [[NASA/IPAC Extragalactic Database]] (NED),{{citation needed|date=August 2020}} 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.<ref>{{cite news |last1=Talbert |first1=Tricia |title=NASA to Reexamine Nicknames for Cosmic Objects |url=https://www.nasa.gov/feature/nasa-to-reexamine-nicknames-for-cosmic-objects |access-date=11 August 2020 |publisher=[[NASA]] |date=11 August 2020}}</ref><ref name="simbad" />
{{clear|left}}
== See also ==

* [[List of planetary nebulae]]
* [[New General Catalogue]]

== Notes ==
{{reflist|group=NB}}
{{refbegin}}
# {{Note label|A|a|none}}Radius = distance × sin(angular size / 2) = ≥2900 ly * sin(48{{pprime}} / 2) = ≥0.34 ly
# {{Note label|B|b|none}}10.1 apparent magnitude – 5 * (log<sub>10</sub>(≥880 pc distance) – 1) = ≤0.4 absolute magnitude
{{refend}}

== References ==
{{reflist}}

== External links ==
{{Commons category}}

* {{WikiSky|name=NGC 2392}}
* [http://antwrp.gsfc.nasa.gov/apod/ap031207.html APOD (2003-12-07)] – NGC 2392
* [https://lowell.edu/eskimo-nebula/ Eskimo Nebula] Lowell Observatory
* [http://www.astro.umd.edu/~jph/eskimo.html The Structure & Evolution of the Eskimo Planetary Nebula] University of Maryland Astronomy Department
* [https://ui.adsabs.harvard.edu/abs/1990ApJ...362..226O/abstract A Kinematic Determination of the Structure of the Double Ring Planetary Nebula NGC 2392, the Eskimo] Astrophysical Journal v.362, p.&nbsp;226 October 1990
* [https://www.cambridge.org/core/services/aop-cambridge-core/content/view/942A16B4A44F063286041BCF49525DF6/S1743921312011453a.pdf/div-class-title-a-cat-s-eye-view-of-the-eskimo-from-saturn-div.pdf A Cat's Eye view of the Eskimo from Saturn] Maria-Teresa Garc ́ıa-D ́ıaz, Jose-Alberto L ́opez, Wofgang Steffen, Michael G. Richer and Hortensia Riesgo, 2011

{{Caldwell catalogue}}
{{NGC objects:2000-2499}}
{{Stars of Gemini}}
{{Portal bar|Astronomy|Stars|Outer space}}
{{Sky|07|29|10.7669|+|20|54|42.488|2870}}
{{DEFAULTSORT:Eskimo Nebula}}
[[Category:Planetary nebulae]]
[[Category:Gemini (constellation)]]
[[Category:NGC objects]]
[[Category:Astronomical objects discovered in 1787|17870117]]
[[Category:Caldwell objects|039b]]