Wikipedia

Omega Virginis

Omega Virginis (ω Vir, ω Virginis) is a solitary[5] star in the zodiac constellation Virgo. It has an apparent visual magnitude of +5.2,[5] which is bright enough to be faintly visible to the naked eye. Based upon an annual stellar parallax shift of 6.56 milliarcseconds,[1] it is located about 500 light years from the Sun.

ω Virginis
Location of ω Virginis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension 11h 38m 27.60727s[1]
Declination +08° 08′ 03.4663″[1]
Apparent magnitude (V) 5.23 - 5.50[2][3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M4 III[5]
U−B color index +1.63[6]
B−V color index +1.60[6]
Variable type LB[2] or SR[3]
Astrometry
Radial velocity (Rv)+5.13±0.52[7] km/s
Proper motion (μ) RA: −3.89[1] mas/yr
Dec.: +5.30[1] mas/yr
Parallax (π)6.56±0.36 mas[1]
Distance500 ± 30 ly
(152 ± 8 pc)
Absolute magnitude (MV)+0.2[8]
Details
Mass1.55[9] M☉
Radius138 ± 17[10][a] R☉
Luminosity2,300±500[10] L☉
Surface gravity (log g)0.8[8] cgs
Temperature3,400±100[10] K
Metallicity [Fe/H]−0.08[8] dex
Other designations
ω Vir, 1 Virginis, BD+08°2532, FK5 2932, HD 101153, HIP 56779, HR 4483, SAO 118965[11]
Database references
SIMBADdata
A light curve for Omega Virginis, plotted from Hipparcos data[12]

This is a red giant star with a stellar classification of M4 III.[5] It is thought to be on the asymptotic giant branch (AGB), with shells of hydrogen and helium around a carbon-oxygen core.[4] After evolving away from the main sequence it has expanded to around 140 times the solar radius,[a] and now shines with 2,300 times the luminosity of the Sun. The effective temperature of the photosphere is 3,400 K.[10]

Omega Virginis is a semiregular variable with a brightness that varies over an amplitude of 0.28 with periods of 30 and 275 days.[13] The General Catalogue of Variable Stars gives the magnitude range as 5.23 to 5.50.[2] It was formally declared a variable star in 1972 following a 1969 study showing small-amplitude variations.[14][15]

Notes

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  1. 1 2 Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of 5,772 K:

References

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  1. 1 2 3 4 5 6 van Leeuwen, F. (November 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, S2CID 18759600.
  2. 1 2 3 Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  3. 1 2 "Omega Vir", International Variable Star Index, AAVSO, retrieved 2022-01-08
  4. 1 2 Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal, 104 (1): 275–313, Bibcode:1992AJ....104..275E, doi:10.1086/116239
  5. 1 2 3 4 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, S2CID 14878976.
  6. 1 2 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
  7. ↑ Famaey, B.; et al. (2009), "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics, 498 (2): 627–640, arXiv:0901.0934, Bibcode:2009A&A...498..627F, doi:10.1051/0004-6361/200810698, S2CID 18739721
  8. 1 2 3 Smith, V.V.; Lambert, D.L. (1986), "The chemical composition of red giants. II - Helium burning and the s-process in the MS and S stars", Astrophysical Journal, 311: 843–863, Bibcode:1986ApJ...311..843S, doi:10.1086/164823
  9. ↑ Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (20 December 2021), "Stellar and substellar companions from Gaia EDR3", Astronomy & Astrophysics, 657: A7, arXiv:2109.10912, Bibcode:2022A&A...657A...7K, doi:10.1051/0004-6361/202142146, eISSN 1432-0746, ISSN 0004-6361
  10. 1 2 3 4 Alonso-Hernández, J.; Sánchez Contreras, C.; Sahai, R.; Sanz-Forcada, J. (2026-04-13), "The dusty envelopes of asymptotic giant branch stars with ultraviolet excesses", Astronomy & Astrophysics, arXiv:2603.19815, doi:10.1051/0004-6361/202659537, ISSN 0004-6361
  11. ↑ "* ome Vir", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2016-09-19.
  12. ↑ "/ftp/cats/more/HIP/cdroms/cats", Centre de Données astronomiques de Strasbourg, Strasbourg astronomical Data Center, retrieved 15 October 2022
  13. ↑ Glass, I. S.; Van Leeuwen, F. (2007), "Semiregular variables in the solar neighbourhood", Monthly Notices of the Royal Astronomical Society, 378 (4): 1543–1549, arXiv:0704.3150, Bibcode:2007MNRAS.378.1543G, doi:10.1111/j.1365-2966.2007.11903.x, S2CID 14332208.
  14. ↑ Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (1973), "59th Name-List of Variable Stars", Information Bulletin on Variable Stars, 834: 1, Bibcode:1973IBVS..834....1K
  15. ↑ Eggen, Olin J. (1969), "Light Variations of Small Amplitude in the Red Giants of the Disc Population", Information Bulletin on Variable Stars, 355 (355, #1. (IBVS Homepage)): 1, Bibcode:1969IBVS..355....1E
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