Sigma Columbae

Sigma Columbae, Latinized from σ Columbae, is a solitary,[10] yellow-white hued star in the southern constellation of Columba. It is faintly visible to the naked eye with an apparent visual magnitude of 5.51.[2] Based upon an annual parallax shift of 1.96 mas as seen from Earth,[1] this star is located roughly 1,700 light years from the Sun.

Sigma Columbae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Columba
Right ascension  05h 56m 20.94287s[1]
Declination −31° 22′ 56.7846″[1]
Apparent magnitude (V) 5.51[2]
Characteristics
Spectral type F2 III[3]
B−V color index +0.39[2]
Astrometry
Radial velocity (Rv)+19.4±2.9[4] km/s
Proper motion (μ) RA: +0.08[1] mas/yr
Dec.: +6.04[1] mas/yr
Parallax (π)1.96 ± 0.24[1] mas
Distanceapprox. 1,700 ly
(approx. 510 pc)
Absolute magnitude (MV)−2.98[5]
Details
Mass3.79[6] M☉
Luminosity1,312[7] L☉
Surface gravity (log g)2.02[6] cgs
Temperature6,820[8] K
Metallicity [Fe/H]−0.91[6] dex
Rotational velocity (v sin i)73.4±3.7[8] km/s
Age400[6] Myr
Other designations
σ Col, CD−31° 2848, HD 40248, HIP 28098, HR 2092, SAO 196330[9]
Database references
SIMBADdata

At an age of about 400 million years,[6] the spectrum of this star suggests this is an evolved F-type giant with a stellar classification of F2 III.[3] It is spinning with a projected rotational velocity of about 74 km/s,[8] which is giving the star an oblate shape with an equatorial bulge that is 10% larger than the polar radius.[11] It has 3.79[6] times the mass of the Sun and is radiating 1,312[7] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 6,820 K.[8]

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.
  2. Høg, E.; et al. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27, Bibcode:2000A&A...355L..27H.
  3. Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H.
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  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. Casagrande, L.; et al. (2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy & Astrophysics, 530 (A138): 21, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
  7. McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  8. Ammler-von Eiff, M.; Reiners, A. (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: 31, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, A116.
  9. "sig Col". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-28.
  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.
  11. 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.
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