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Not to be confused with T Centauri.
τ Centauri
Location of τ Centauri (circled)
Observation data
Epoch J2000.0       Equinox J2000.0 ( ICRS)
Constellation Centaurus
Right ascension 12h 37m 42.16377s [1]
Declination −48° 32′ 28.6899″ [1]
Apparent magnitude (V) +3.86 [2]
Characteristics
Spectral type A0 V [3] or A1 IVnn [4]
U−B color index +0.04 [2]
B−V color index +0.06 [2]
Astrometry
Radial velocity (Rv)+5.5±2.3 [5] km/s
Proper motion (μ) RA: −186.26 [1]  mas/ yr
Dec.: −6.01 [1]  mas/ yr
Parallax (π)24.85 ± 0.53  mas [1]
Distance131 ± 3  ly
(40.2 ± 0.9  pc)
Absolute magnitude (MV)+0.83 [6]
Details
Mass2.31 [7]  M☉
Radius2.2 [8]  R☉
Luminosity42 [6]  L☉
Surface gravity (log g)4.02±0.14 [7]  cgs
Temperature10,533±358 [7]  K
Rotational velocity (v sin i)296.8±3.8 [9] km/s
Age132 [7]  Myr
Other designations
τ Cen, CD−47° 7745, HD 109787, HIP 61622, HR 4802, SAO 223560 [10]
Database references
SIMBAD data

Tau Centauri, Latinized from τ Centauri, is a solitary [11] star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of +3.86. [2] The distance to this star, based upon an annual parallax shift of 24.85  mas, [1] is 131  light years. There is a 98% chance that it is a co-moving companion of Gamma Centauri; the two stars have an estimated separation of 1.7 ly (0.53 pc). [12]

This is an A-type star with stellar classifications of A0 V [3] or A1 IVnn, [4] indicating it may be a main sequence star or a more evolved subgiant star. It is around 132 [7] million years old and is spinning rapidly with a projected rotational velocity of 296.8 [9] km/s. This is giving the star an oblate shape, with an estimated equatorial girth that is 30% larger than the polar radius. [13] The star has an estimated 2.3 [7] times the mass of the Sun and 2.2 [8] times the Sun's radius.

References

  1. ^ a b c d e f 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, S2CID  18759600.
  2. ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD Astronomical Database, Bibcode: 1986EgUBV........0M.
  3. ^ a b Lagrange, A.-M.; et al. (February 2009), "Extrasolar planets and brown dwarfs around A-F type stars. VI. High precision RV survey of early type dwarfs with HARPS", Astronomy and Astrophysics, 495 (1): 335–352, arXiv: 0809.4636, Bibcode: 2009A&A...495..335L, doi: 10.1051/0004-6361:200810105, S2CID  62894956.
  4. ^ a b Gray, R. O.; Garrison, R. F. (July 1989), "The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation", Astrophysical Journal Supplement Series, 70 (4): 623–636, Bibcode: 1989ApJS...70..623G, doi: 10.1086/191349.
  5. ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv: 1208.3048, Bibcode: 2012A&A...546A..61D, doi: 10.1051/0004-6361/201219219, S2CID  59451347, A61.
  6. ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971, Bibcode: 2012AstL...38..331A, doi: 10.1134/S1063773712050015, S2CID  119257644.
  7. ^ a b c d e f 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: 1501.03154, Bibcode: 2015ApJ...804..146D, doi: 10.1088/0004-637X/804/2/146, S2CID  33401607.
  8. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (3rd ed.): 521–524, arXiv: astro-ph/0012289, Bibcode: 2001A&A...367..521P, doi: 10.1051/0004-6361:20000451, S2CID  425754.
  9. ^ a b Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics, 531: A143, arXiv: 1012.4858, Bibcode: 2011A&A...531A.143D, doi: 10.1051/0004-6361/201016386, S2CID  119286673.
  10. ^ "* tau Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-01-13.{{ cite web}}: CS1 maint: postscript ( link)
  11. ^ De Rosa, R. J.; et al. (January 2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society, 437 (2): 1216–1240, arXiv: 1311.7141, Bibcode: 2014MNRAS.437.1216D, doi: 10.1093/mnras/stt1932, S2CID  88503488.
  12. ^ Shaya, Ed J.; Olling, Rob P. (January 2011), "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue", The Astrophysical Journal Supplement, 192 (1): 2, arXiv: 1007.0425, Bibcode: 2011ApJS..192....2S, doi: 10.1088/0067-0049/192/1/2, S2CID  119226823
  13. ^ Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv: 1204.2572, Bibcode: 2012A&ARv..20...51V, doi: 10.1007/s00159-012-0051-2, S2CID  119273474.
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