Astronomy:NGC 6723

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NGC 6723
A globular cluster. It is made up of many thousands of bright stars, tightly-packed in the centre and more spread out at the corners, but filling the entire view. The stars are coloured either orange or bright blue, with the blue stars mainly concentrated in the centre. Orange stars are located mainly around the edge, and also vary in size from small dots to glowing stars with four points, based on their position in the foreground or background of the cluster.
NGC 6723 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
ClassVII[1]
ConstellationSagittarius
Right ascension 18h 59m 33.15s[2]
Declination–36° 37′ 56.1″[2]
Distance28.4 kly (8.7 kpc)[3]
Apparent magnitude (V)6.8[4]
Apparent dimensions (V)11′[4]
Physical characteristics
Mass3.57×105[3] M☉
Metallicity[Fe/H] = –0.96[5] dex
Estimated age13.06 Gyr[5]
Other designationsChandelier Cluster, ESO 396-SC 010, CD−36 13199, HD 175980, 2MASS J18593296-3637528[6][7]
See also: Globular cluster, List of globular clusters

NGC 6723 (also known as the Chandelier Cluster)[8] is a globular cluster in the constellation Sagittarius. It was discovered by British astronomer James Dunlop on 2 June 1826.[9] Its magnitude is given as between 6 and 6.8, and its diameter is between 7 and 11 arcminutes. It is a class VII cluster with stars of magnitude 14 and dimmer. It is near the border of Sagittarius and Corona Australis.

Unlike common globular clusters, NGC 6723 has an enhanced metallicity and a large fraction of younger stars, with primordial stars accounting for only 0.363±0.017 % of the total.[10]

Map showing location of NGC 6723

See also

References

  1. ↑ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin 849 (849): 11–14, Bibcode: 1927BHarO.849...11S. 
  2. ↑ 2.0 2.1 Goldsbury, Ryan et al. (December 2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal 140 (6): 1830–1837, doi:10.1088/0004-6256/140/6/1830, Bibcode: 2010AJ....140.1830G. 
  3. ↑ 3.0 3.1 Boyles, J. et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal 742 (1): 51, doi:10.1088/0004-637X/742/1/51, Bibcode: 2011ApJ...742...51B. 
  4. ↑ 4.0 4.1 "Data for NGC 6723". http://www.ngcicproject.org. 
  5. ↑ 5.0 5.1 Forbes, Duncan A.; Bridges, Terry (May 2010), "Accreted versus in situ Milky Way globular clusters", Monthly Notices of the Royal Astronomical Society 404 (3): 1203–1214, doi:10.1111/j.1365-2966.2010.16373.x, Bibcode: 2010MNRAS.404.1203F. 
  6. ↑ "NGC 6723". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+6723. 
  7. ↑ "Results for object NGC 6723". NASA and Caltech. https://ned.ipac.caltech.edu/byname?objname=NGC+6723. 
  8. ↑ Stoyan, Ronald; Schurig, Stephan (2014). interstellarum Deep Sky Atlas. Erlangen: Cambridge University Press; Oculum-Verlag GmbH. ISBN 978-1-107-50338-0. OCLC 920437579. http://www.deep-sky-atlas.com/. 
  9. ↑ Seligman, Courtney. "New General Catalogue Objects: NGC 6723". https://cseligman.com/text/atlas/ngc67.htm#6723. 
  10. ↑ Lee, Jae-Woo (2019), "Multiple Stellar Populations of Globular Clusters from Homogeneous Ca–CN–CH Photometry. V. cn′JWL as a Surrogate cnJWL Index and NGC 6723", The Astrophysical Journal 883 (2): 166, doi:10.3847/1538-4357/ab3d34 
  • Robert Burnham Jr, Burnham's Celestial Handbook: An observer's guide to the universe beyond the solar system, vol 3, p. 1558

Coordinates: Sky map 18h 59m 33.15s, −36° 37′ 56.1″



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