Upsilon Tauri

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υ Tauri
Taurus constellation map.svg
Red circle.svg
Location of υ Tauri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Taurus
Right ascension 04h 26m 18.46368s[1]
Declination +22° 48′ 48.8885″[1]
Apparent magnitude (V) +4.28[2]
Spectral type A8 Vn[3]
U−B color index +0.14[4]
B−V color index +0.25[4]
Radial velocity (Rv)32.2±1.1[5] km/s
Proper motion (μ) RA: +108.81[1] mas/yr
Dec.: −46.80[1] mas/yr
Parallax (π)21.21 ± 0.25[1] mas
Distance154 ± 2 ly
(47.1 ± 0.6 pc)
Absolute magnitude (MV)+0.91[6]
Mass1.55[7] M
Radius1.803[8] R
Luminosity32.5[9] L
Surface gravity (log g)3.50[7] cgs
Temperature7,398±252[7] K
Rotation0.415 d[8]
Rotational velocity (v sin i)243[3] km/s
Age827[7] Myr
Other designations
υ Tau, υ1 Tau, 69 Tauri, BD+22 696, FK5 2326, HD 28024, HIP 20711, HR 1392, SAO 76608[10]
Database references

Upsilon Tauri (υ Tauri) is a solitary,[11] white-hued star in the zodiac constellation of Taurus, and is a member of the Hyades star cluster.[8] It is faintly visible to the naked eye with an apparent visual magnitude of +4.28.[2] Based upon an annual parallax shift of 21.21 mas seen from Earth, it is around 154 light years from the Sun.

This is an A-type main sequence star with a stellar classification of A8 Vn.[3] It is classified as a Delta Scuti type variable star and its brightness varies from magnitude +4.28 to +4.31 with a period of 3.56 hours.[2] At an estimated age of 827 million years,[7] it is spinning rapidly with a rotation period of just 0.415 days.[8] This is giving the star an oblate shape with an equatorial bulge that is 9% larger than the polar radius.[12]

Occasionally this star system shares the Bayer designation υ Tauri with , which is separated from it by 0.29° in the sky.[13]


With φ, κ1, κ2 and χ, it composed the Arabic were the Arabs' Al Kalbain, the Two Dogs.[14] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Kalbain were the title for five stars : φ as Alkalbain I, χ as Alkalbain II, κ1 as Alkalbain III, κ2 as Alkalbain IV and this star (υ) as Alkalbain V.[15]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. ^ a b c Solano, E.; Fernley, J. (April 1997), "Spectroscopic survey of delta Scuti stars. I. Rotation velocities and effective temperatures", Astronomy & Astrophysics Supplement Series, 122: 131–147, Bibcode:1997A&AS..122..131S, doi:10.1051/aas:1997329.
  3. ^ a b c 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/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
  4. ^ a b Danziger, I. J.; Dickens, R. J. (July 1967), "Spectrophotometry of New Short-Period Variable Stars", Astrophysical Journal, 149: 55, Bibcode:1967ApJ...149...55D, doi:10.1086/149231.
  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. ^ 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 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 c d van Saders, Jennifer L.; Pinsonneault, Marc H. (October 2013), "Fast Star, Slow Star; Old Star, Young Star: Subgiant Rotation as a Population and Stellar Physics Diagnostic", The Astrophysical Journal, 776 (2): 20, arXiv:1306.3701, Bibcode:2013ApJ...776...67V, doi:10.1088/0004-637X/776/2/67, S2CID 119097746, 67.
  9. ^ 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:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
  10. ^ "ups Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-05.{{cite web}}: CS1 maint: postscript (link)
  11. ^ 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.
  12. ^ van Belle, Gerard T. (March 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.
  13. ^ Hoffleit, D.; Jaschek, C. (1991). The Bright Star Catalogue. New Haven: Yale University Observatory.
  14. ^ Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, p. 413
  15. ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology.
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