Tau Virginis

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τ Virginis
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension 14h 01m 38.79341s[1]
Declination +01° 32′ 40.3145″[1]
Apparent magnitude (V) 4.2777±0.0007[2]
Characteristics
Spectral type A2IV/V[3]
U−B color index +0.12[4]
B−V color index +0.11[4]
Astrometry
Radial velocity (Rv) −6.7±0.9[5] km/s
Proper motion (μ) RA: +17.49[1] mas/yr
Dec.: −21.27[1] mas/yr
Parallax (π) 14.50 ± 0.18[1] mas
Distance 225 ± 3 ly
(69.0 ± 0.9 pc)
Absolute magnitude (MV) +0.5[6]
Details
Mass 1.96[7] M
Radius 1.6[8] R
Luminosity 70[9] L
Surface gravity (log g) 3.39[7] cgs
Temperature 8,413±286[7] K
Metallicity [Fe/H] −0.19[10] dex
Rotational velocity (v sin i) 186[11] km/s
Age 724[7] Myr
Other designations
τ Vir, 93 Virginis, BD+02° 2761, FK5 516, HD 122408, HIP 68520, HR 5264, SAO 120238.[12]

Tau Virginis (τ Vir, τ Virginis) is a single[13] star in the zodiac constellation Virgo. With an apparent visual magnitude of 4.28,[2] it is faintly visible to the naked eye. The distance to Tau Virginis, based upon parallax measurements, is approximately 225 light years with a margin of error of ±3 light years.

This star has a stellar classification of A2IV/V,[3] which matches the spectrum of an A-type main sequence star mixed with spectral traits of a subgiant. It is about 700[7] million years old and is spinning rapidly with a projected rotational velocity of 186 km/s.[11] The star has nearly double[7] the mass of the Sun and about 160% of the Sun's radius.[8] It shines with 70[9] times the luminosity of the Sun and has an effective temperature of 8413 K in its outer atmosphere.[7]

Tau Virginis has multiple visual companions, listed below:[14]

Companion Visual
Magnitude
Angular
Separation
Position
Angle
Year
Measured
B 9.41 82.70 287° 2012
C 13.10 176.70″ 353° 2000
D 9.68 342.70″ 85° 2012
E 12.00 14.6″ 175° 2009

References[edit]

  1. ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752free to read, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b Adelman, S. J. (February 2001). "Research Note Hipparcos photometry: The least variable stars". Astronomy and Astrophysics. 367 (1): 297–298. Bibcode:2001A&A...367..297A. doi:10.1051/0004-6361:20000567. 
  3. ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5", Michigan Spectral Survey, 05, Bibcode:1999MSS...C05....0H 
  4. ^ a b Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, Bibcode:1986EgUBV........0M 
  5. ^ Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065. 
  6. ^ Blondel, P. F. C.; Djie, H. R. E. Tjin A. (September 2006), "Modeling of PMS Ae/Fe stars using UV spectra", Astronomy and Astrophysics, 456 (3): 1045−1068, Bibcode:2006A&A...456.1045B, doi:10.1051/0004-6361:20040269. 
  7. ^ a b c d e f g David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154free to read, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146. 
  8. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289free to read, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  9. ^ a b 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:1208.2037free to read, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x. 
  10. ^ Morossi, C.; et al. (September 2002), "Metallicity Determinations from Ultraviolet-Visual Spectrophotometry. I. The Test Sample", The Astrophysical Journal, 577 (1): 377−388, Bibcode:2002ApJ...577..377M, doi:10.1086/342144. 
  11. ^ a b Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785free to read, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224. 
  12. ^ "tau Vir -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-09-16. 
  13. ^ 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:0806.2878free to read, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  14. ^ Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.