Astronomy:31 Comae Berenices

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Short description: Star in the constellation Coma Berenices
31 Comae Berenices
Location of 31 Comae Berenices (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Coma Berenices[1]
Right ascension  12h 51m 41.91900s[2]
Declination +27° 32′ 26.5683″[2]
Apparent magnitude (V) 4.87 - 4.97[3]
Characteristics
Evolutionary stage Subgiant[4]
Spectral type G0III[5]
Variable type FK Com[3]
Astrometry
Proper motion (μ) RA: −10.990[2] mas/yr
Dec.: −8.313[2] mas/yr
Parallax (π)11.4933 ± 0.1828[2] mas
Distance284 ± 5 ly
(87 ± 1 pc)
Absolute magnitude (MV)_0.05[1]
Details
Mass2.2[6] M☉
Radius8.9[5] R☉
Luminosity74[5] L☉
Surface gravity (log g)3.51[5] cgs
Temperature5,660[5] K
Metallicity [Fe/H]−0.15[5] dex
Rotation6.8 d[5]
Rotational velocity (v sin i)67[5] km/s
Age540[7] Myr
Other designations
31 Com, LS Comae Berenices, BD+28°2156, FK5 1332, HD 111812, HIP 62763, HR 4883, SAO 82537[8]
Database references
SIMBADdata

31 Comae Berenices (31 Com) is a yellow giant star in the constellation Coma Berenices. Its apparent magnitude is about 4.9 and slightly variable. It is visible to the naked eye. In 1997, Klaus G. Strassmeier et al. announced their discovery that the star is a variable star.[9] It was given its variable star designation, LS Comae Berenices, in 2003.[10] It is a rare FK Comae Berenices variable, a variable star that spins rapidly and has large starspots on its surface.[8] It is currently in the Hertzsprung gap and its outer envelope has just begun convection.[4] In 1989 it was given as a spectral standard for the class G0IIIp.[11]

A visual band light curve for 31 Comae Berenices, adapted from Strassmeier et al. (1997).[9] The red line shows the linear least squares fit to the data.

31 Com is the north galactic pole star, and occasionally goes by the informal name Polaris Galacticum Borealis, coined by Jim Kaler.[12]

In Chinese astronomy, 31 Comae Berenices is called 郎將, Pinyin: Lángjiāng, meaning Captain of the Bodyguards, because this star is marking itself and stand alone in Captain of the Bodyguards asterism, Supreme Palace enclosure mansion (see: Chinese constellation).[13]

References

  1. ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A  XHIP record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. 
  3. ↑ 3.0 3.1 Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S. 
  4. ↑ 4.0 4.1 Strassmeier, K. G. et al. (September 2010), "Rotation and magnetic activity of the Hertzsprung-gap giant 31 Comae", Astronomy and Astrophysics 520: 14, doi:10.1051/0004-6361/201015023, A52, Bibcode: 2010A&A...520A..52S. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Aurière, M. et al. (February 2015), "The magnetic fields at the surface of active single G-K giants", Astronomy & Astrophysics 574: 30, doi:10.1051/0004-6361/201424579, A90, Bibcode: 2015A&A...574A..90A. 
  6. ↑ Olivares, J.; Lodieu, N.; Béjar, V. J. S.; Martín, E. L.; Žerjal, M.; Galli, P. A. B. (2023). "The cosmic waltz of Coma Berenices and Latyshev 2 (Group X). Membership, phase-space structure, mass, and energy distributions". Astronomy and Astrophysics 675. doi:10.1051/0004-6361/202244703. Bibcode: 2023A&A...675A..28O. 
  7. ↑ Seli, B.; Oláh, K.; Kriskovics, L.; Kővári, Zs.; Vida, K.; Balázs, L. G.; Laming, J. M.; Van Driel-Gesztelyi, L. et al. (2022). "Extending the FIP bias sample to magnetically active stars. Challenging the FIP bias paradigm". Astronomy and Astrophysics 659. doi:10.1051/0004-6361/202141493. Bibcode: 2022A&A...659A...3S. 
  8. ↑ 8.0 8.1 "31 Com". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=31+Com. 
  9. ↑ 9.0 9.1 Strassmeier, K. G.; Bartus, J.; Cutispoto, G.; Rodono, M. (October 1997). "Starspot photometry with robotic telescopes: Continuous UBV and V(RI)_C photometry of 23 stars in 1991-1996". Astronomy & Astrophysics Supplement Series 125: 11–63. doi:10.1051/aas:1997369. Bibcode: 1997A&AS..125...11S. https://aas.aanda.org/articles/aas/pdf/1997/13/ds1287.pdf. Retrieved 29 January 2025. 
  10. ↑ Kazarovets, E. V.; Kireeva, N. N.; Samus, N. N.; Durlevich, O. V. (May 2003). "The 77th Name-List of Variable Stars". Information Bulletin on Variable Stars 5422: 1–56. Bibcode: 2003IBVS.5422....1K. https://ibvs.konkoly.hu/pub/ibvs/5401/5422.pdf. Retrieved 29 January 2025. 
  11. ↑ Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K 
  12. ↑ "Polaris Galacticum Borealis". http://stars.astro.illinois.edu/sow/pgb.html. 
  13. ↑ Ian Ridpath's Startales - Coma Berenices the Berenice's Hair



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