Omicron Columbae

Omicron Columbae is a star in the southern constellation Columba. It has an apparent visual magnitude of 4.81,[2] which is bright enough to be faintly visible to the naked eye. The distance to this star, as determined by an annual parallax shift of 30.82 mas,[1] is 105.8 light years. The visual magnitude is reduced by an interstellar absorption factor of 0.06 due to intervening dust.[5]

Omicron Columbae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Columba
Right ascension 05h 17m 29.08929s[1]
Declination −34° 53′ 42.7444″[1]
Apparent magnitude (V) 4.81[2]
Characteristics
Spectral type K1 IV[3] or K1 III[2]
U−B color index +0.80[4]
B−V color index +1.00[4]
Astrometry
Radial velocity (Rv)21.10±0.09[5] km/s
Proper motion (μ) RA: +92.67[1] mas/yr
Dec.: −336.23[1] mas/yr
Parallax (π)30.82 ± 0.20[1] mas
Distance105.8 ± 0.7 ly
(32.4 ± 0.2 pc)
Absolute magnitude (MV)+2.17±0.04[6]
Details[5]
Mass1.57±0.07 M☉
Radius5.04±0.14 R☉
Luminosity15.5 L☉
Surface gravity (log g)3.19±0.03 cgs
Temperature4,936±28 K
Metallicity [Fe/H]−0.04±0.04 dex
Rotational velocity (v sin i)1.2[2] km/s
Age2.17±0.28 Gyr
Other designations
ο Col, CD−35° 2214, FK5 197, HD 34642, HIP 24659, HR 1743, SAO 195721.[7]
Database references
SIMBADdata

Depending on the source, this star has been given a stellar classification of K1 III[2] or K1 IV,[3] suggesting that it is a K-type star currently in the subgiant or giant stage of its evolution. It has 1.57 times the Sun's mass and has expanded to more than five times the radius of the Sun.[5] The star appears to be spinning slowly with a projected rotational velocity of 1.2 km/s,[2] and is around 2.2 billion years old. It is estimated to radiate 15.5 times the solar luminosity from its outer atmosphere at an effective temperature of 4,936 K.[5]

Omicron Columbae is a high proper motion star that may share a common proper motion with the object WISE J051723.87−345121.8. The two have an angular separation of 159 arc seconds.[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. Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1.
  3. Gray, R. O.; et al. (2003), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I", The Astronomical Journal, 126 (4): 2048, arXiv:astro-ph/0308182, Bibcode:2003AJ....126.2048G, doi:10.1086/378365.
  4. Cousins, A. W. J.; et al. (1969), "Comparison Stars for Long Period Variables", Monthly Notes of the Astronomical Society of Southern Africa, 28: 63, Bibcode:1969MNSSA..28...63C.
  5. 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.
  6. da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105.
  7. "omi Col -- High proper-motion Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-01-02.
  8. Luhman, K. L.; Sheppard, Scott S. (June 2014), "Characterization of High Proper Motion Objects from the Wide-field Infrared Survey Explorer", The Astrophysical Journal, 787 (2): 12, arXiv:1404.6505, Bibcode:2014ApJ...787..126L, doi:10.1088/0004-637X/787/2/126, 126.
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