NGC 4833

Coordinates: Sky map 12h 59m 34.98s, −70° 52′ 28.6″
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NGC 4833
NGC 4833 is one of the over 150 globular clusters known to reside within the Milky Way.[1]
Observation data (J2000 epoch)
Right ascension12h 59m 33.92s[3]
Declination–70° 52′ 35.4″[3]
Distance21.5 kly (6.6 kpc)[4]
Apparent magnitude (V)+7.79[5]
Apparent dimensions (V)13.5
Physical characteristics
Mass4.10×105[4] M
Radius42 ly[6]
Metallicity = –1.71[7] dex
Estimated age12.54 Gyr[7]
Other designationsCaldwell 105, GCl 21,[5] Lacaille I.4
Dunlop 164, Bennett 56
See also: Globular cluster, List of globular clusters
The location of NGC 4833 (labelled in red)

NGC 4833 (also known as Caldwell 105) is a globular cluster discovered by Abbe Lacaille during his 1751-1752 journey to South Africa, and catalogued in 1755. It was subsequently observed and catalogued by James Dunlop and Sir John Herschel whose instruments could resolve it into individual stars.

The globular cluster is situated in the very southerly constellation Musca at a distance of 21,200 light years from Earth. It is partially obscured by a dusty region of the galactic plane. After corrections for the reddening by dust, evidence was obtained that it is in the order of 2 billion years older than globular clusters M5 or M92.

See also[edit]


  1. ^ "A sky full of stars". Retrieved 1 August 2016.
  2. ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14, Bibcode:1927BHarO.849...11S.
  3. ^ a b 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, arXiv:1008.2755, Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830, S2CID 119183070.
  4. ^ a b Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal, 742 (1): 51, arXiv:1108.4402, Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51, S2CID 118649860.
  5. ^ a b "NGC 4833". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-17.
  6. ^ distance × tan( diameter_angle / 2 ) = 42 ly. radius
  7. ^ a b 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, arXiv:1001.4289, Bibcode:2010MNRAS.404.1203F, doi:10.1111/j.1365-2966.2010.16373.x, S2CID 51825384.
  1. CCD Photometry of the Globular Cluster NGC 4833 and Extinction Near the Galactic Plane, Melbourne et al., 25 September 2000, Astrophysical Journal

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