Gamma Comae Berenices
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 12h 26m 56.273s[1] |
| Declination | +28° 16′ 06.318″[1] |
| Apparent magnitude (V) | 4.36[2] |
| Characteristics | |
| Spectral type | K1 III Fe0.5[3] |
| U−B color index | +1.16[2] |
| B−V color index | +1.13[2] |
| R−I color index | +0.51[4] |
| Astrometry | |
| Radial velocity (Rv) | +3.38±0.11[5] km/s |
| Proper motion (μ) | RA: −83.006 mas/yr[1] Dec.: −80.917 mas/yr[1] |
| Parallax (π) | 19.8641±0.1147 mas[1] |
| Distance | 164.2 ± 0.9 ly (50.3 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.76[6] |
| Details[7] | |
| Mass | 1.65±0.18 M☉ |
| Radius | 12.01+0.36 −0.34[8] R☉ |
| Luminosity | 61.4±3.3[8] L☉ |
| Surface gravity (log g) | 2.53±0.05 cgs |
| Temperature | 4,660±84[8] K |
| Metallicity [Fe/H] | 0.16±0.10 dex |
| Rotational velocity (v sin i) | ≤ 17[4] km/s |
| Age | 2.72±0.78 Gyr |
| Other designations | |
| γ Com, 15 Comae Berenices, BD+29°2288, FK5 2999, GC 16964, HD 108381, HIP 60742, HR 4737, SAO 82313, PPM 101903[9] | |
| Database references | |
| SIMBAD | data |
Gamma Comae Berenices is a single,[10] orange-hued star in the northern constellation of Coma Berenices. Its name is a Bayer designation that is Latinized from γ Comae Berenices, and abbreviated Gamma Com or γ Com. This star is faintly visible to the naked eye, having an apparent visual magnitude of 4.36.[2] Based upon an annual parallax shift of 19.86 mas as seen from Earth,[1] its distance can be estimated as around 167 light years from the Sun. The star is moving away from the Sun with a radial velocity of +3 km/s.[5]
This is an evolved K-type giant star with a stellar classification of K1 III Fe0.5.[3] The suffix notation indicates the star displays an overabundance of iron in its spectrum. It is most likely (91% chance) on the horizontal branch with an age of 2.7 billion years. If this is true, then it has an estimated 1.65 times the mass of the Sun and has expanded to nearly 12 times the Sun's radius. The star is radiating 58 times the Sun's luminosity from its enlarged photosphere at an effective temperature of around 4,652 K.[7] Gamma Comae Berenices appears as part of the Coma Star Cluster, although it is probably not actually a member of this cluster.[11]
R. H. Allen's Star Names attributes the name Al Ḍafīrah to this star, from an Arabic name for the Coma Star Cluster.[12] In Chinese astronomy, it is identified as Lángwèiyī (郎位一), meaning it is the first star of the asterism Lángwèi (郎位, Officers of the Imperial Guard).[13][14]
References
- 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875 Gaia DR3 record for this source at VizieR.
- 1 2 3 4 Haupt, H. F.; Schroll, A. (1974), "Photoelektrische Photometrie von Shell-Sternen", Astronomy and Astrophysics Supplement Series, 15: 311, Bibcode:1974A&AS...15..311H.
- 1 2 Keenan, Philip C; McNeil, Raymond C (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- 1 2 Hoffleit, D.; Warren, Jr., W. H., "HR 4737 database entry", The Bright Star Catalogue (5th Revised (Preliminary Version) ed.)
- 1 2 Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304
- ↑ Hekker, S.; et al. (August 2006), "Precise radial velocities of giant stars. I. Stable stars", Astronomy and Astrophysics, 454 (3): 943–949, arXiv:astro-ph/0604502, Bibcode:2006A&A...454..943H, doi:10.1051/0004-6361:20064946, S2CID 119529768
- 1 2 Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy and Astrophysics, 574A (2): 116–129, arXiv:1412.4634, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360, S2CID 59334290.
- 1 2 3 Baines, Ellyn K.; et al. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155 (1), 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b, S2CID 119427037.
- ↑ "gam Com", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2010-10-12
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ↑ Tonkin, Stephen F. (2007), Binocular astronomy, Springer, p. 124, ISBN 978-1-84628-308-6.
- ↑ Allen, R. H. (1963) [1899], Star Names: Their Lore and Meaning (Dover ed.), p. 171, retrieved 2026-06-15
- ↑ "AEEA 天文教育資訊網" [Activities of Exhibition and Education in Astronomy] (in Chinese). Archived from the original on 1 December 2023.
- ↑ "Langwei (郎位)". All Skies Encyclopaedia. IAU Working Group on Star Names. Retrieved 1 August 2025.
