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Omega Virginis

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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☉
Radius109[10] R☉
Luminosity1,470[10] L☉
Surface gravity (log g)0.8[8] cgs
Temperature3,433[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

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.

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 109 times the solar radius, and now shines with 1,470 times the luminosity of the Sun. The effective temperature of the photosphere is 3,433 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]

References

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  1. ^ a b c d e f 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. ^ a b c 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. ^ a b "Omega Vir", International Variable Star Index, AAVSO, retrieved 2022-01-08
  4. ^ a b 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. ^ a b c d 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. ^ a b 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. ^ a b c 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. ^ a b c d McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017-10-01), "Fundamental parameters and infrared excesses of Tycho-Gaia stars", Monthly Notices of the Royal Astronomical Society, 471: 770–791, arXiv:1706.02208, Bibcode:2017MNRAS.471..770M, doi:10.1093/mnras/stx1433, ISSN 0035-8711 Omega Virginis' database entry at VizieR.
  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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