Astronomy:NGC 2204

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NGC 2204
NGC 2204, Digitized Sky Survey
Observation data (J2000.0 epoch)
ConstellationCanis Major
Right ascension 06h 15m 31.7s[1]
Declination−18° 40′ 12″[1]
Distance13.4 ± 1.3 kly (4.1 ± 0.4 kpc)[2]
Apparent magnitude (V)8.6[3]
Apparent dimensions (V)10.0′[3]
Physical characteristics
Radius16.25ly
Estimated age2.0±0.3 Gyr[2]
Other designationsCollinder 88, Melotte 44[4]
See also: Open cluster, List of open clusters

NGC 2204 is an open cluster of stars in the Canis Major constellation. It was discovered by the German-English astronomer William Herschel on 6 February 1785.[5] The cluster has an integrated visual magnitude of 8.6 and spans a diameter of 10.0′. Resolving the individual member stars is a challenge with a 10 to 12-inch amateur telescope.[3] It is located at a distance of approximately 13,400 light years from the Sun.[2] The cluster shows a mean radial velocity of +91.38±0.30 km/s relative to the Sun,[6] and is orbiting the inner galactic disk region about 1 kpc below the galactic plane.[2]

This is a rich but diffuse cluster with a Trumpler class of III 3m,[7][8] spanning a physical diameter of about 55 ly (17 pc).[9] It is an older cluster with an estimated age of 2.0±0.3 billion years.[10] The metallicity is correspondingly poor,[11][8] showing an abundance of iron about 59% of that in the Sun.[2] There is a prominent giant branch clump on the HR diagram.[7] The cluster has a significant population of blue stragglers,[12][11] an indicator of past stellar mergers. It has a pair of candidate chemically peculiar stars,[8] and five variable stars have been discovered, including four eclipsing variables.[9]

References

  1. ↑ 1.0 1.1 Tarricq, Y. et al. (March 2021). "3D kinematics and age distribution of the open cluster population". Astronomy & Astrophysics 647: id. A19. doi:10.1051/0004-6361/202039388. Bibcode: 2021A&A...647A..19T. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Jacobson, Heather R. et al. (February 2011). "A Chemical Abundance Study of Red Giants in Open Clusters NGC 2204 and NGC 2243". The Astronomical Journal 141 (2): 16. doi:10.1088/0004-6256/141/2/58. 58. Bibcode: 2011AJ....141...58J. 
  3. ↑ 3.0 3.1 3.2 O'Meara, Stephen James (2007). Herschel 400 Observing Guide. Cambridge University Press. p. 48. ISBN 9780521858939. https://books.google.com/books?id=Nyh9fAC_tpIC&pg=PA48. 
  4. ↑ "NGC 2204". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+2204. 
  5. ↑ Frommert, Hartmut; Kronberg, Christine. "NGC 2204". http://messier.seds.org/xtra/ngc/n2204.html. 
  6. ↑ Mermilliod, J. -C.; Mayor, M. (August 2007). "Red giants in open clusters. XII. Six old open clusters NGC 2112, 2204, 2243, 2420, 2506, 2682". Astronomy and Astrophysics 470 (3): 919–926. doi:10.1051/0004-6361:20077198. Bibcode: 2007A&A...470..919M. 
  7. ↑ 7.0 7.1 Hawarden, T. G. (January 1976). "NGC 2204: an old open cluster in the halo". Monthly Notices of the Royal Astronomical Society 174: 225–239. doi:10.1093/mnras/174.1.225. Bibcode: 1976MNRAS.174..225H. 
  8. ↑ 8.0 8.1 8.2 Dawson, D. W. (February 1981). "The open cluster NGC 2204". Astronomical Journal 86: 237–241. doi:10.1086/112879. Bibcode: 1981AJ.....86..237D. 
  9. ↑ 9.0 9.1 Rozyczka, M. et al. (December 2007). "Variable Stars in the Field of the Open Cluster NGC2204". Acta Astronomica 57: 323–329. Bibcode: 2007AcA....57..323R. 
  10. ↑ Salaris, M. et al. (January 2004). "The age of the oldest Open Clusters". Astronomy and Astrophysics 414 (2): 163–174. doi:10.1051/0004-6361:20031578. Bibcode: 2011AJ....141...58J. 
  11. ↑ 11.0 11.1 Siegel, Michael H. et al. (July 2019). "The Swift UVOT Stars Survey. III. Photometry and Color-Magnitude Diagrams of 103 Galactic Open Clusters". The Astronomical Journal 158 (1): id. 35. doi:10.3847/1538-3881/ab21e1. Bibcode: 2019AJ....158...35S. 
  12. ↑ Frogel, J. A.; Twarog, B. A. (November 1983). "Faint stellar photometry in clusters. I. NGC 2204 and E3". Astrophysical Journal 274: 270–285. doi:10.1086/161445. Bibcode: 1983ApJ...274..270F. 

Template:NGC objects:2000-2499

Coordinates: Sky map 06h 15m 33s, −18° 39′ 54″



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