Omicron Virginis

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ο Virginis
Virgo constellation map.svg
Red circle.svg

Location of ο Virginis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Virgo
Right ascension 12h 05m 12.54049s[1]
Declination +08° 43′ 58.7498″[1]
Apparent magnitude (V) 4.12[2]
Spectral type G8 IIIa CN-1Ba1CH1[3]
Radial velocity (Rv) −29.62[4] km/s
Proper motion (μ) RA: −218.69[1] mas/yr
Dec.: +57.76[1] mas/yr
Parallax (π) 19.98 ± 0.22[1] mas
Distance 163 ± 2 ly
(50.1 ± 0.6 pc)
Absolute magnitude (MV) +0.52[5]
Mass 2.17 M
Radius 9.62 R
Luminosity 57 L
Surface gravity (log g) 3.17 cgs
Temperature 5,107 K
Metallicity [Fe/H] −0.30 dex
Rotational velocity (v sin i) 2.23 km/s
Age 0.88 Gyr
Other designations
9 Virginis, ο Vir, BD+09°2583, FK5 450, GJ 3703, HD 104979, HIP 58948, HR 4608, SAO 119213
Database references

Omicron Virginis (ο Vir, ο Virginis) is a star in the zodiac constellation of Virgo. It is visible to the naked eye with an apparent visual magnitude of +4.12.[5] Based upon parallax measurements, it is about 163 light years from the Sun.

ο Virginis is a G-type giant star with a stellar classification of G8 IIIa CN-1Ba1CH1.[3] This indicates that it is a Barium star. Typically Barium stars are close binaries with a white dwarf companion, but no companion ihas been detected for ο Virginis.[6] It has been suggested that an excess SiIV emission flux is due to an unseen white dwarf companion.[7]

ο Virginis is a giant star around tens times larger than the sun. Although it is slightly cooler, it is radiating about 60-132 times the luminosity of the Sun. It is over twice as massive as the sun and is around a billion years old.[5][4] A simplified statistical analysis suggests that ο Virginis is likely to be a red giant branch star fusing hydrogen in a shell around an inert helium core, but there is about a 22% chance that it is a horizontal branch star fusing helium in its core.[8]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M. 
  3. ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373. 
  4. ^ a b c Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; de la Villarmois, E. Artur; Chavero, C.; Gómez, M.; Mauas, P. J. D. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. 
  5. ^ a b c Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434Freely accessible, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781. 
  6. ^ Začs, Laimons (2000). "The Chemical Composition and Orbital Parameters of Barium Stars". The Carbon Star Phenomenon. 177: 277. Bibcode:2000IAUS..177..277Z. 
  7. ^ Böhm-Vitense, Erika; Carpenter, Kenneth; Robinson, Richard; Ake, Tom; Brown, Jeffery (2000). "Do All BA II Stars Have White Dwarf Companions?". The Astrophysical Journal. 533 (2): 969. Bibcode:2000ApJ...533..969B. doi:10.1086/308678. 
  8. ^ Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas (2015). "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity". Astronomy & Astrophysics. 574: A116. Bibcode:2015A&A...574A.116R. doi:10.1051/0004-6361/201322360.