NGC 2174

NGC 2174 (also known as Monkey Head Nebula) is an H II[1] emission nebula located in the constellation Orion and is associated with the open star cluster NGC 2175.[1] It is thought to be located about 6,400 light-years away from Earth. The nebula may have formed through hierarchical collapse.[2]

NGC 2174
Emission nebula
H II region
Stellar nursery NGC 2174 by HST
Credit: ESA/Hubble & NASA
Observation data: J2000 epoch
Right ascension 06h 09.7m[1]
Declination+20° 30′[1]
Distance6,400 ly   (2,000 pc)
Apparent magnitude (V)6.8
Apparent dimensions (V)40′
ConstellationOrion

There is some equivocation in the use of the identifiers NGC 2174 and NGC 2175. These may apply to the entire nebula, to its brightest knot, or to the star cluster it includes. Burnham's Celestial Handbook lists the entire nebula as 2174/2175 and does not mention the star cluster.[3] The NGC Project (working from the original descriptive notes) assigns NGC 2174 to the prominent knot at J2000  06h 09m 23.7s, +20° 39′ 34″ and NGC 2175 to the entire nebula, and by extension to the star cluster.[4] Simbad uses NGC 2174 for the nebula and NGC 2175 for the star cluster.[1] [5]

Hubble 24th Anniversary Images (2014)
Further information: List of Hubble anniversary images
24th anniversary image – 2014 – A set of Infrared images of Monkey Head Nebula incl. NGC 2174 and Sharpless Sh2-252[6]
  • Infrared image of NGC 2174 as viewed by the Spitzer Space Telescope
  • Monkey Head Nebula in hydrogen alpha focal length 384mm
  • Monkey Head Nebula in bi-color with a 384mm telescope
  • Monkey Head Nebula in Narrowband Sulfur-Hydrogen Alpha- Oxygen with a 384mm telescope credit: Stephan Hamel
gollark: It seems like the problem is some somewhat broken optimization, where `pcall` somehow directly executes the real `getfenv`, ignorant of environments, if you have a function which only (or something like that?) calls a builtin. Or possibly not only builtins.
gollark: I have a fix, but it would be mildly bad for `pcall` performance so I don't want to implement it...
gollark: That sounds hilariously inefficient and probably wouldn't fix it.
gollark: How can I even patch this‽
gollark: But if I don't, it does that?!

References
  1. "NGC 2174". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 13 July 2011.
  2. Cotera, A.; Hester, J.; Healy, K.; Snider, K.; et al. (August 2006). Using Spitzer IRAC observations to Compare Modes of Star Formation in G305.35+0.7 and NGC 2174/5. Triggered Star Formation in a Turbulent ISM, International Astronomical Union Symposium. Prague, Czech Republic (published 2006). Bibcode:2006IAUS..237E..98C. S237, #98.
  3. Robert Burnham, Jr, Burnham's Celestial Handbook, Dover, 1978, p. 1280.
  4. "Public Database". NGC/IC Project. Results for NGC 2174 and NGC 2175. Archived from the original on 28 May 2009. Retrieved 12 January 2014.
  5. "SIMBAD Astronomical Database". Results for NGC 2175. Retrieved 13 January 2014.
  6. "Hubble Celebrates 24th Anniversary with Infrared Image of Nearby Star Factory". 17 March 2014.
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