14 Comae Berenices

14 Comae Berenices is a single[3] star in the northern constellation of Coma Berenices, and is the second brightest[8] member of the Coma Star Cluster.[3] It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.95.[2] Parallax measurements place the star at a distance of about 266 light years.[1]

14 Comae Berenices
Location of 14 Com (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Coma Berenices
Right ascension  12h 26m 24.06461s[1]
Declination +27° 16′ 05.6845″[1]
Apparent magnitude (V) 4.95[2]
Characteristics
Spectral type F0p[3][4]
U−B color index +0.18[2]
B−V color index +0.277±0.018[5]
Astrometry
Radial velocity (Rv)−2.20[6] km/s
Proper motion (μ) RA: −16.010[1] mas/yr
Dec.: −13.412[1] mas/yr
Parallax (π)12.2564 ± 0.2329[1] mas
Distance266 ± 5 ly
(82 ± 2 pc)
Absolute magnitude (MV)+0.35[7]
Details[8]
Mass2.4[7] M☉
Radius23 R☉
Luminosity76.01[5] L☉
Surface gravity (log g)3.4[8] cgs
Temperature7,300 K
Rotational velocity (v sin i)226[7] km/s
Age500 Myr
Other designations
14 Com, BD+28°2115, FK5 2997, HD 108283, HIP 60697, HR 4733, SAO 82310[9]
Database references
SIMBADdata

The spectrum of this star is peculiar and it has been assigned a number of different stellar classifications: A5, F0p, F0 III Sr, F0 vp,[3] F1 IV: np Sr shell,[5] A9 IV np Sr II,[10] F1 IV,[11] and A9 V + shell.[12] Abt & Morrell (1995) designated this a Lambda Boötis star but this was later refuted.[10] No surface magnetic field has been detected on 14 Comae Bernices.[13]

14 Comae Berenices is a well-known[12][8] shell star with a high rate of spin, showing a projected rotational velocity of 226 km/s.[7] This is giving the star an oblate shape with an equatorial bulge that is 12% larger than the polar radius.[4] It is radiating 76[5] times the Sun's luminosity from its photosphere at an effective temperature of 7,300 K.[8]

References
  1. 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.
  2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. Abou Elazm, M. S. (October 1993), "The composite spectrum of the A type star 14 Comae", Astrophysics and Space Science, 208 (1): 1–4, Bibcode:1993Ap&SS.208....1A, doi:10.1007/BF00658127
  4. van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2
  5. 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.
  6. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  7. Pizzolato, N.; et al. (2000). "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases". Astronomy and Astrophysics. 361: 614. Bibcode:2000A&A...361..614P.
  8. Dominy, J. F.; Smith, M. A. (1977). "A spectroscopic study of 14 Comae and other A-type shell stars". Astrophysical Journal. 217: 494. Bibcode:1977ApJ...217..494D. doi:10.1086/155598.
  9. "14 Com". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-02.
  10. Murphy, Simon J.; et al. (October 2015), "An Evaluation of the Membership Probability of 212 λ Boo Stars. I. A Catalogue", Publications of the Astronomical Society of Australia, 32: 43, arXiv:1508.03633, Bibcode:2015PASA...32...36M, doi:10.1017/pasa.2015.34, e036
  11. Gray, R. O.; et al. (2001). "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars". The Astronomical Journal. 121 (4): 2148. Bibcode:2001AJ....121.2148G. doi:10.1086/319956.
  12. Abt, Helmut A.; Willmarth, Daryl W. (August 1999), "Binaries in the Praesepe and Coma Star Clusters and Their Implications for Binary Evolution", The Astrophysical Journal, 521 (2): 682–690, Bibcode:1999ApJ...521..682A, doi:10.1086/307569
  13. Kudryavtsev, D. O.; et al. (November 2006). "New magnetic chemically peculiar stars". Monthly Notices of the Royal Astronomical Society. 372 (4): 1804–1828. Bibcode:2006MNRAS.372.1804K. doi:10.1111/j.1365-2966.2006.10994.x.
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