Trifid Nebula

Trifid Nebula
Emission nebula
H II region
reflection nebula and dark nebula
Observation data: J2000 epoch
Right ascension18h 02m 23s[1]
Declination−23° 01′ 48″[1]
Distance4100±200[2] ly   (1,260±70 pc)
Apparent magnitude (V)+6.3[1]
Apparent dimensions (V)28 arcmins
ConstellationSagittarius
Physical characteristics
Radius21 ly
Notable featuresa
DesignationsM20, NGC 6514,[1] Sharpless 30, RCW 147, Gum 76
See also: Lists of nebulae

The Trifid Nebula (catalogued as Messier 20 or M20 and as NGC 6514) is an H II region in the north-west of Sagittarius in a star-forming region in the Milky Way's Scutum–Centaurus Arm.[3] It was discovered by Charles Messier on June 5, 1764.[4] Its name means 'three-lobe'. The object is an unusual combination of an open cluster of stars, an emission nebula (the relatively dense, reddish-pink portion), a reflection nebula (the mainly NNE blue portion), and a dark nebula (the apparent 'gaps' in the former that cause the trifurcated appearance, also designated Barnard 85). Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, and is thus a perennial favorite of amateur astronomers.[5]

The most massive star that has formed in this region is HD 164492A, an O7.5III star with a mass more than 20 times the mass of the Sun.[6] This star is surrounded by a cluster of approximately 3100 young stars.[7]

  1. ^ a b c d "NGC 6514". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-16.
  2. ^ Kuhn, Michael A.; Hillenbrand, Lynne A.; Sills, Alison; Feigelson, Eric D.; Getman, Konstantin V. (2018). "Kinematics in Young Star Clusters and Associations with Gaia DR2". The Astrophysical Journal. 870 (1): 32. arXiv:1807.02115. Bibcode:2019ApJ...870...32K. doi:10.3847/1538-4357/aaef8c. S2CID 119328315.
  3. ^ Cambrésy, L.; et al. (2011). "Variation of the extinction law in the Trifid nebula". Astronomy & Astrophysics. 527: A141. arXiv:1101.1089. Bibcode:2011A&A...527A.141C. doi:10.1051/0004-6361/201015863. S2CID 39501333.
  4. ^ Messier 20
  5. ^ "Trifid Nebula: A Massive Star Factory". Science Daily. August 26, 2009. Retrieved 2010-07-06.
  6. ^ Rho, J.; et al. (2004). "Chandra Observation of the Trifid Nebula: X-Ray Emission from the O Star Complex and Actively Forming Pre-Main-Sequence Stars". Astrophysical Journal. 607 (2): 904–912. arXiv:astro-ph/0401377. Bibcode:2004ApJ...607..904R. doi:10.1086/383081. S2CID 119090269.
  7. ^ Kuhn, M. A.; et al. (2015). "The Spatial Structure of Young Stellar Clusters. II. Total Young Stellar Populations". Astrophysical Journal. 802 (1): 60. arXiv:1501.05300. Bibcode:2015ApJ...802...60K. doi:10.1088/0004-637X/802/1/60. S2CID 119309858.