This cluster is about 29 kly (8.9 kpc) from the Galactic Center and is currently orbiting in the Milky Wayhalo. It may be associated with the Monoceros Ring—a long tidal stream of stars that could have been formed from a disrupted dwarf galaxy. NGC 5286 may be one of the oldest globular clusters in the galaxy,[6] with an estimated age of 12.54 billion years.[5] It is not perfectly spherical, but has a projected ellipticity of 0.12.[6]
The velocity dispersion of stars at the center of the cluster is (8.1 ± 1.0) km/s. Based upon the motions of stars at the core of this cluster, it may host an intermediate mass black hole with less than 1% of the cluster's mass. The upper limit for the mass estimate of this object is 6,000 times the mass of the Sun.[6]
NGC 5286 is part of the Gaia Sausage, the hypothesised remains of a merged dwarf galaxy.[8]
References
^Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14, Bibcode:1927BHarO.849...11S.