Messier Index/M12
Messier 12 or M 12 (also designated NGC 6218) is a w:globular cluster in the w:constellation of w:Ophiuchus. It was discovered by w:Charles Messier on w:May 30, w:1764.
| M12 | |
|---|---|
 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 | kg ( M) |
| Radius | 37.2 ly[2] |
| Other designations | NGC 6218[1] |
Located roughly 3° in the sky from the cluster M10, M12 is about 16,000 w:light-years from Earth and has a spatial diameter of about 75 light-years. The brightest stars of M12 are of 12th magnitude. It is rather loosely packed for a globular and was once thought to be a tightly concentrated w:open cluster. Thirteen w:variable stars have been recorded in this cluster.
A study published in w:2006 concluded that this cluster has an unusually low number of low mass stars. The authors surmise that they were stripped from the cluster by the gravitational influence of the w:Milky Way.[1]
