Gamma Comae Berenices

Gamma Comae Berenices, Latinized from γ Comae Berenices, is a single,[10] orange-hued star in the northern constellation of Coma Berenices. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.36.[2] Based upon an annual parallax shift of 19.50 mas as seen from Earth, 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]

γ Comae Berenices
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Coma Berenices
Right ascension 12h 26m 56.27207s[1]
Declination +28° 16′ 06.3211″[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: −83.990 ± 0.418[6] mas/yr
Dec.: −82.216 ± 0.345[6] mas/yr
Parallax (π)19.2552 ± 0.2371 mas[6]
Distance169 ± 2 ly
(51.9 ± 0.6 pc)
Absolute magnitude (MV)0.76[7]
Details[8]
Mass1.65±0.18 M☉
Radius11.76±0.14 R☉
Luminosity58.2±1.1 L☉
Surface gravity (log g)2.53±0.05 cgs
Temperature4,652±18 K
Metallicity [Fe/H]0.16±0.10 dex
Rotational velocity (v sin i)≤ 17[4] km/s
Age2.72±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
SIMBADdata

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.[8] Gamma Comae Berenices appears as part of the Coma Star Cluster, although it is probably not actually a member of this cluster.[11]

References
  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. Haupt, H. F.; Schroll, A. (1974), "Photoelektrische Photometrie von Shell-Sternen", Astronomy and Astrophysics Supplement Series, 15: 311, Bibcode:1974A&AS...15..311H.
  3. 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.
  4. Hoffleit, D.; Warren, Jr., W. H., "HR 4737 database entry", The Bright Star Catalogue (5th Revised (Preliminary Version) ed.)
  5. 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
  6. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  7. 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
  8. 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.
  9. * gam Com -- Star in Cluster, database entry, SIMBAD. Accessed on line October 12, 2010.
  10. 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.
  11. Tonkin, Stephen F. (2007), Binocular astronomy, Springer, p. 124, ISBN 978-1-84628-308-6.
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