Messier 12
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Messier 12, from 2MASS |
|
| Observation data: J2000 epoch | |
|---|---|
| Class: | IX |
| Constellation: | Ophiuchus |
| Right ascension: | 16h 47m 14.52s[1] |
| Declination: | -01° 56′ 52.1″[1] |
| Distance: | 16.0 kly (4.9 kpc) |
| Apparent magnitude (V): | +7.68[1] |
| Apparent dimensions (V): | 16′.0 |
| Physical characteristics | |
| Mass: | ( M☉) |
| Radius: | 37.2 ly[2] |
| VHB: | |
| Estimated age: | |
| Notable features: | |
| Other designations: | NGC 6218[1] |
| See also: Globular cluster, List of globular clusters | |
Messier 12 (also known as M12, Globular Cluster M12 or NGC 6218) is a globular cluster in the constellation Ophiuchus. It was discovered by Charles Messier on May 30, 1764.
Located roughly 3° from the cluster M10, M12 is about 16,000 light-years distant and has a spatial diameter of ~75 light-years. The brightest stars of M12 are of 12th magnitude. It is rather loosely packed for a globular and M12 was once thought to be a tightly concentrated open cluster. Thirteen variable stars have been recorded in this cluster.
A study published in 2006 concluded that this cluster lost about one million stars of low mass, and therefore has an unusually low number of such stars. The authors surmise that they were stripped from the cluster by the gravitational influence of the Milky Way [1].
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