M62 is about 21.5 kly[3] from
Earth and 5.5 kly from the
Galactic Center.[2] It is among the ten most massive and luminous globular clusters in the
Milky Way, showing an integrated
absolute magnitude of −9.18.[5] It has an estimated mass of 1.22×106M☉[6] and a mass-to-light ratio of 2.05±0.04 in the core visible light band, the
V band.[12] It has a projected
ellipticity of 0.01, meaning it is essentially spherical.[13] The density profile of its member stars suggests it has not yet undergone
core collapse.[14] It has a core radius of 1.3 ly (0.39 pc), a half-mass radius of 9.6 ly (2.95 pc), and a half-light radius of 6.0 ly (1.83 pc). The stellar density at the core is 5.13 M☉ per cubic parsec.[15] It has a
tidal radius of 59 ly (18.0 pc).[8]
The cluster shows at least two distinct populations of stars, which most likely represent two separate episodes of star formation. Of the
main sequence stars in the cluster, 79%±1% are from the first generation and 21%±1% from the second. The second is polluted by materials released by the first. In particular, abundances of helium, carbon, magnesium, aluminium, and sodium differ between these two.[5]
Indications are this is an
Oosterhoff type I, or "
metal-rich" system. A 2010 study identified 245
variable stars in the cluster's field, of which 209 are
RR Lyrae variables, four are
Type II Cepheids, 25 are
long period variables, and one is an
eclipsing binary. The cluster may prove to be the galaxy's richest in terms of RR Lyrae variables.[16] It has ten binary millisecond
pulsars, including one (M62B) that is displaying eclipsing behavior from gas streaming off its companion,[17] and one (M62H) with a
planetary-mass companion about three times the mass of Jupiter.[18] There are multiple
X-ray sources, including 50 within the half-mass radius.[14] 47
blue straggler candidates have been identified, formed from the merger of two stars in a binary system, and these are preferentially concentrated near the core region.[14]
It is hypothesized that this cluster may be host to an
intermediate mass black hole (IMBH) – it is considered well-suited for searching for such an object. A brief study, before 2013, of the
proper motion of stars within 17
″ of the core did not require an IMBH to explain. However, simulations can not rule out one with a mass of a few thousand
M☉. Based upon
radial velocity measurements within an
arcsecond of the core, Kiselev
et al. (2008) made the claim of an IMBH, likewise with mass of (1–9)×103M☉.[12]
^Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14,
Bibcode:
1927BHarO.849...11S.
^
abOliveira, R. A. P.; Ortolani, S.; Barbuy, B.; Kerber, L. O.; Maia, F. F. S.; Bica, E.; Cassisi, S.; Souza, S. O.; Pérez-Villegas, A. (2022). "Precise distances from OGLE-IV member RR Lyrae stars in six bulge globular clusters". Astronomy & Astrophysics. 657: A123.
arXiv:2110.13943.
Bibcode:
2022A&A...657A.123O.
doi:
10.1051/0004-6361/202141596.
S2CID239998638.
^"Messier 62". SEDS Messier Catalog. Retrieved 29 April 2022.
^McNamara, Bernard J.; McKeever, Jean (November 2011), "The Dynamical Distance, RR Lyrae Absolute Magnitude, and Age of the Globular Cluster NGC 6266", The Astronomical Journal, 142 (5): 4,
Bibcode:
2011AJ....142..163M,
doi:10.1088/0004-6256/142/5/163, 163.
^Baumgardt, H.; Hilker, M. (August 2018), "A catalogue of masses, structural parameters, and velocity dispersion profiles of 112 Milky Way globular clusters", Monthly Notices of the Royal Astronomical Society, 478 (2): 1520–1557,
arXiv:1804.08359,
Bibcode:
2018MNRAS.478.1520B,
doi:
10.1093/mnras/sty1057.
^In daily rising of this star, whether in day- or nighttime, it will reach 15° above the due southern horizon, at the 90°−30°−15° parallel thus the
45th parallel north, the furthest north for very detailed observation for this object
Wikimedia Commons has media related to Messier 62.
Frommert, Hartmut; Kronberg, Christine (August 30, 2007),
Messier 62, Students for the Exploration and Development of Space (SEDS), retrieved 2018-11-29.