Coma Star Cluster

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Coma Star Cluster
Melotte 111, taken from a rural location in Derbyshire, England, in March 2003.
Observation data (J2000 epoch)
ConstellationComa Berenices
Right ascension 12h 22.5m[1]
Declination+25° 51′[1]
Distance280 ly (86 pc[2][3])
Apparent magnitude (V)+1.8
Apparent dimensions (V)7.5° [2]
Physical characteristics
Estimated age-
Other designationsMelotte 111,[1] Coma Ber Cluster,[1] OCl 558.0,[1] Collinder 256[4]
See also: Open cluster, List of open clusters

The Coma Star Cluster in Coma Berenices, designated Melotte 111 after its entry in the catalogue of star clusters 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 approximately 86 parsecs (280 ly).[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 legendary sacrifice of her hair.

Brightest members
(mv < 6.5)[5]
Identifier Magnitude
γ Com[a] 4.81
12 Com 4.81
31 Com 4.94
14 Com 4.95
16 Com 4.96
13 Com 5.18
17 Com 5.24
21 Com 5.44
18 Com[b] 5.47
HD 106887 5.71
HD 105805 5.99
8 Com 6.22
22 Com 6.24
FM Com 6.43
  1. ^ Outside a nominal 5° radius adopted as the cluster size
  2. ^ At the same distance as Melotte 111, but its proper motion and isochrone are inconsistent.


See also[edit]


  1. ^ a b c d e "Cl Melotte 111 -- Open (galactic) Cluster". SIMBAD. Retrieved 23 October 2013.
  2. ^ a b c d van Leeuwen, F. (April 2009). "Parallaxes and proper motions for 20 open clusters as based on the new Hipparcos catalogue". Astronomy and Astrophysics. 497 (1): 209–242. arXiv:0902.1039. Bibcode:2009A&A...497..209V. doi:10.1051/0004-6361/200811382.
  3. ^ a b c Majaess, D.; Turner, D.; Lane, D.; Krajci, T. (September 2011). "Deep Infrared ZAMS Fits to Benchmark Open Clusters Hosting Delta Scuti Stars". Journal of the American Association of Variable Star Observers. 39 (2): 219. arXiv:1102.1705. Bibcode:2011JAVSO..39..219M.
  4. ^ Houston, Walter Scott. "Open Clusters by the Season". Sky & Telescope. p. 8. Retrieved 23 October 2013.
  5. ^ Tang, Shih-Yun; Chen, W. P.; Chiang, P. S.; Jose, Jessy; Herczeg, Gregory J.; Goldman, Bertrand (2018). "Characterization of Stellar and Substellar Members in the Coma Berenices Star Cluster". The Astrophysical Journal. 862 (2): 106. arXiv:1806.08322. Bibcode:2018ApJ...862..106T. doi:10.3847/1538-4357/aacb7a.

External links[edit]

Coordinates: Sky map 12h 22m 30s, +25° 51′ 00″