Messier 15
Messier 15 or M15 (also designated NGC 7078) is a globular cluster in the constellation Pegasus. It was discovered by Jean-Dominique Maraldi in 1746 and included in Charles Messier's catalogue of comet-like objects in 1764. At an estimated 12.5±1.3 billion years old, it is one of the oldest known globular clusters.
| Messier 15 | |
|---|---|
Deep Broadband (RGB) image of M15 | |
| Observation data (J2000 epoch) | |
| Class | IV |
| Constellation | Pegasus |
| Right ascension | 21h 29m 58.33s |
| Declination | +12° 10′ 01.2″ |
| Distance | 35.69 ± 0.43 kly (10.944 ± 0.131 kpc) |
| Apparent magnitude (V) | 6.2 |
| Apparent dimensions (V) | 18′.0 |
| Physical characteristics | |
| Mass | 5.6×105 M☉ |
| Radius | ~88 ly |
| VHB | 15.83 |
| Metallicity | = –2.37 dex |
| Estimated age | 12.0 Gyr |
| Notable features | steep central cusp |
| Other designations | NGC 7078, GCl 120 |
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