7 Comae Berenices

7 Comae Berenices is a single[6] star located 249[1] light years away in the northern constellation of Coma Berenices. It is a dim star but visible to the naked eye near the Coma Star Cluster with an apparent visual magnitude of 4.93.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −28 km/s,[4] and is predicted to come as close as 83 light-years in 2.4 million years.[2]

7 Comae Berenices
Observation data
Epoch 2000.0      Equinox 2000.0
Constellation Coma Berenices
Right ascension 12h 16m 20.53831s[1]
Declination +23° 56′ 43.4700″[1]
Apparent magnitude (V) 4.93[2]
Characteristics
Evolutionary stage horizontal branch
Spectral type G8 III–IIIb[3]
B−V color index 0.957[2]
Astrometry
Radial velocity (Rv)−27.89±0.13[4] km/s
Proper motion (μ) RA: −26.55[1] mas/yr
Dec.: −6.22[1] mas/yr
Parallax (π)13.08 ± 0.30[1] mas
Distance249 ± 6 ly
(76 ± 2 pc)
Absolute magnitude (MV)+0.51[2]
Details[4]
Mass2.37±0.16 M☉
Radius10.07±0.66 R☉
Luminosity63+14
−12 L☉
Surface gravity (log g)2.95±0.08 cgs
Temperature5,023±25 K
Metallicity [Fe/H]−0.09±0.05 dex
Rotational velocity (v sin i)2.26±0.45 km/s
Age730±150 Myr
Other designations
7 Com, BD+24°2443, FK5 2982, HD 106714, HIP 59847, HR 4667, SAO 82211[5]
Database references
SIMBADdata

This is an evolved giant star with a stellar classification of G8 III–IIIb.[3] At the age of 730 million years it is a red clump giant, which indicates it is on the horizontal branch and is generating energy via helium fusion at its core.[7] The star has 2.4 times the mass of the Sun and has expanded to 10 times the Sun's radius. It is radiating about 63 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,023 K.[4]

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. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  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. Jofré, E.; et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics, 574: A50, arXiv:1410.6422, Bibcode:2015A&A...574A..50J, doi:10.1051/0004-6361/201424474, S2CID 53666931.
  5. "7 Com". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 30, 2018.
  6. 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.
  7. Mishenina, T. V.; et al. (September 2006), "Elemental abundances in the atmosphere of clump giants", Astronomy and Astrophysics, 456 (3): 1109–1120, arXiv:astro-ph/0605615, Bibcode:2006A&A...456.1109M, doi:10.1051/0004-6361:20065141, S2CID 18764566.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.