Astronomy:Upsilon Tauri

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υ Tauri
Taurus constellation map.svg
Red circle.svg
Location of υ Tauri (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Taurus
Right ascension  04h 26m 18.46368s[1]
Declination +22° 48′ 48.8885″[1]
Apparent magnitude (V) 4.28 – 4.31[2]
Characteristics
Spectral type A8 Vn[3]
U−B color index +0.14[4]
B−V color index +0.25[4]
Variable type δ Scuti[2]
Astrometry
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]
Details
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
SIMBADdata

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 +4.3. Based upon an annual parallax shift of 21.21 mas seen from Earth, it is around 154 light years from the Sun.

Properties

A light curve for Upsilon Tauri, plotted from TESS data[12]

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.[13]

Occasionally this star system shares the Bayer designation υ Tauri with 72 Tauri, which is separated from it by 0.29° in the sky.[14]

Naming

With φ, κ1, κ2 and χ, it composed the Arabic were the Arabs' Al Kalbain, the Two Dogs.[15] 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.[16]

References

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  3. 3.0 3.1 3.2 Royer, F. et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode2007A&A...463..671R. 
  4. 4.0 4.1 Danziger, I. J.; Dickens, R. J. (July 1967), "Spectrophotometry of New Short-Period Variable Stars", Astrophysical Journal 149: 55, doi:10.1086/149231, Bibcode1967ApJ...149...55D. 
  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, doi:10.1051/0004-6361/201219219, A61, Bibcode2012A&A...546A..61D. 
  6. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  7. 7.0 7.1 7.2 7.3 7.4 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, doi:10.1088/0004-637X/804/2/146, Bibcode2015ApJ...804..146D. 
  8. 8.0 8.1 8.2 8.3 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, doi:10.1088/0004-637X/776/2/67, 67, Bibcode2013ApJ...776...67V. 
  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, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode2012MNRAS.427..343M. 
  10. "ups Tau". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ups+Tau. 
  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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  12. MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 8 December 2021. 
  13. van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode2012A&ARv..20...51V. 
  14. Hoffleit, D.; Jaschek, C. (1991), The Bright Star Catalogue, New Haven: Yale University Observatory, Bibcode1991bsc..book.....H. 
  15. Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, p. 413 
  16. Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf.