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FK Comae Berenices is a variable star that varies in apparent magnitude between 8.14m and 8.33m over a period of 2.4 days. It is the prototype for the FK Coma Berenices (FK Com) class of variable stars. The variability of FK Com stars may be caused by large, cool spots on the rotating surfaces of the stars. This star is thought to be the result of a recent binary merger, resulting in a high rate of both spin and magnetic activity.[4]

FK Comae Berenices
Observation data
Epoch J2000      Equinox J2000
Constellation Coma Berenices
Right ascension  13h 30m 46.79937s[1]
Declination +24° 13′ 57.7862″[1]
Apparent magnitude (V) 8.17
Spectral type G4 III[2]
Variable type FK Com
Radial velocity (Rv)−21.0±5.8[2] km/s
Proper motion (μ) RA: –51.969[1] mas/yr
Dec.: –22.262[1] mas/yr
Parallax (π)4.6102 ± 0.0446[1] mas
Distance707 ± 7 ly
(217 ± 2 pc)
Absolute magnitude (MV)1.2[3]
Luminosity30 L
Rotational velocity (v sin i)160[4] km/s
Other designations
BD+24°2592, HD 117555, HIP 65915, SAO 82867[5]
Database references


  1. ^ a b c d e 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. ^ a b Strassmeier, Klaus G. (September 2009), "Starspots", The Astronomy and Astrophysics Review, 17 (3): 251–308, Bibcode:2009A&ARv..17..251S, doi:10.1007/s00159-009-0020-6.
  3. ^ Korhonen, H., Berdyugina, S. V., Hackman, T., Duemmler, R., Ilyin, I. V., & Tuominen, I., (1999). "Study of FK Comae Berenices. I. Surface images for 1994 and 1995". Astronomy and Astrophysics. 346: 103. Bibcode:1999A&A...346..101K.CS1 maint: Uses authors parameter (link)
  4. ^ a b Ayres, Thomas R.; et al. (March 2016), "FK Comae Berenices, King of Spin: The COCOA-PUFS Project", The Astrophysical Journal Supplement Series, 223 (1): 30, arXiv:1601.03305, Bibcode:2016ApJS..223....5A, doi:10.3847/0067-0049/223/1/5, 5.
  5. ^ "FK Com". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-06.

External linksEdit