Messier 62
Template:Short description Template:Infobox globular cluster
Messier 62 or M62, also known as NGC 6266 or the Flickering Globular Cluster, is a globular cluster of stars in the southTemplate:Efn of the equatorial constellation of Ophiuchus. It was discovered in 1771 by Charles Messier,Template:Efn then added to his catalogue eight years later.<ref name=Thompson2007/>
M62 is about Template:Val<ref name=Oliveira/> from Earth and Template:Val from the Galactic Center.<ref name=DiCriscienzo2006/> It is among the ten most massive and luminous globular clusters in the Milky Way, showing an integrated absolute magnitude of −9.18.<ref name=Milone2015/> It has an estimated mass of Template:Val<ref name=Boyles2011/> and a mass-to-light ratio of Template:Val in the core visible light band, the V band.<ref name=McNamara2012/> It has a projected ellipticity of 0.01, meaning it is essentially spherical.<ref name=McNamara2011/> The density profile of its member stars suggests it has not yet undergone core collapse.<ref name=Beccari2006/> It has a core radius of Template:Convert, a half-mass radius of Template:Convert, and a half-light radius of Template:Convert. The stellar density at the core is Template:Val per cubic parsec.<ref name=Baumgardt2018/> It has a tidal radius of Template:Convert.<ref name=Mackey2005/>
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, Template:Val are from the first generation and Template:Val from the second. The second is enriched by elements released by the first. In particular, abundances of helium, carbon, magnesium, aluminium, and sodium differ between these two.<ref name=Milone2015/>
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.<ref name=Contreras2010/> It has ten binary millisecond pulsars, including one (M62B) that is displaying eclipsing behavior from gas streaming off its companion,<ref name=Cocozza2008/> and one (M62H) with an orbiting exoplanet about three times the mass of Jupiter.<ref name="Vleeschower2024"/> There are multiple X-ray sources, including 50 within the half-mass radius.<ref name=Beccari2006/> 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.<ref name=Beccari2006/>
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 Template:Val of the core did not require an IMBH to explain. However, simulations can not rule out one with a mass of a few thousand Template:Solar mass in M62's core. For example, based upon radial velocity measurements within an arcsecond of the core, Kiselev et al. (2008) made the claim of an IMBH in M15, likewise with mass of Template:Val.<ref name=McNamara2012/>
GalleryEdit
- Messier 62 Hubble WikiSky.jpg
Messier 62 by the Hubble Space Telescope; Template:Val field of view
- M62HunterWilson.jpg
Globular Cluster M62 - wide field view
- M62map.png
Map showing the location of M62.
See alsoEdit
References and footnotesEdit
Template:Reflist Template:Notelist
External linksEdit
- Template:Citation
- Messier 62, Galactic Globular Clusters Database page
- M62 on willig.net
- Template:WikiSky
Template:Sky Template:Portal bar Template:Messier objects Template:Ngc65 Template:Ophiuchus