| Coma Star Cluster | |
|---|---|
Melotte 111, taken from a rural location in Derbyshire, England, in March 2003. |
|
| Observation data (J2000 epoch) | |
| Constellation | Coma Berenices |
| Right ascension | 12h 22.5m[1] |
| Declination | +25° 51′[1] |
| Distance | 280 ly (86 pc[2][3]) |
| Apparent magnitude (V) | +1.8 |
| Apparent dimensions (V) | 7.5° [2] |
| Physical characteristics | |
| Mass | - M☉ |
| Radius | - |
| Estimated age | - |
| Other designations | Melotte 111,[1] Coma Ber Cluster,[1] OCl 558.0[1] |
| See also: Open cluster, List of open clusters | |
Not to be confused with the Coma cluster of galaxies.
The Coma Star Cluster in Coma Berenices, designated Melotte 111 after its entry in the catalogue of deep sky objects by P. J. Melotte, is a small but nearby star cluster in our galaxy, containing about 40 brighter stars (magnitude 5 to 10) with a common proper motion. The Hipparcos satellite and infrared color-magnitude diagram fitting have been used to establish a distance to the cluster's center of ~86 pc.[2][3] The distance established via the independent analyses agree, thereby making the cluster an important rung on the cosmic distance ladder. The open cluster is roughly twice as distant as the Hyades and covers an area of more than 7.5 degrees on the sky.[2][3] The cluster is approximately 450 million years old. In the FOV of a good field glass most of its stars can be seen simultaneously. The brighter stars of the cluster make out a distinctive "V" shape as seen when Coma Berenices is rising.
It used to represent Leo's tail, but Ptolemy III, in around 240 BC, renamed it for the Egyptian queen Berenice's sacrifice of her hair in a legend.