Sigma2 Tauri

Sigma2 Tauri
Location of σ2 Tauri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Taurus
Right ascension 04h 39m 16.50230s
Declination +15° 55′ 04.7029″
Apparent magnitude (V) 4.70
Characteristics
Evolutionary stage main sequence
Spectral type A5 Vn
U−B color index +0.13
B−V color index +0.14
Astrometry
Radial velocity (Rv)+40.8±1.2 km/s
Proper motion (μ) RA: +83.17 mas/yr
Dec.: −20.97 mas/yr
Parallax (π)20.97±0.27 mas
Distance156 ± 2 ly
(47.7 ± 0.6 pc)
Absolute magnitude (MV)+1.28
Details
Mass1.71 M☉
Radius1.9 R☉
Luminosity22.5 L☉
Surface gravity (log g)3.96 cgs
Temperature8,165±278 K
Metallicity [Fe/H]0.10±0.11 dex
Rotational velocity (v sin i)128 km/s
Age258 Myr
Other designations
92 Tauri, BD+15°666, FK5 2345, HD 29488, HIP 21683, HR 1479, SAO 94054, WDS J04393+1555A
Database references
SIMBADdata

Sigma2 Tauri (σ2 Tauri) is the Bayer designation for a white-hued star in the zodiac constellation of Taurus. It has an apparent visual magnitude of +4.70, which indicates it is visible to the naked eye. Based upon parallax measurements, σ2 Tauri is about 156 light-years distant.

σ2 Tauri is a solitary A-type main sequence star with a stellar classification of A5 Vn. The 'n' suffix indicates the lines are "nebulous" due to rapid rotation, and indeed it is spinning with a projected rotational velocity of 128 km/s. The star is an estimated 258 million years old, with 1.7 times the mass of the Sun. It is radiating 22.5 times the Sun's luminosity from its photosphere at an effective temperature of around 8,165 K. The star is considered a member of the Hyades cluster.

In Chinese astronomy, σ2 Tauri is called 附耳, Pinyin: Fùěr, meaning Whisper, because this star is marking itself and stands alone in the Whisper asterism of the Net mansion (see: Chinese constellation).

References

  1. 1 2 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. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 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.
  3. 1 2 3 4 Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  4. ↑ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  5. 1 2 3 4 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.
  6. ↑ 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.
  7. 1 2 3 4 5 6 7 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. 1 2 Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  9. 1 2 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. ↑ Soubiran, C.; et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
  11. ↑ "sig02 Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-06.{{cite web}}: CS1 maint: postscript (link)
  12. ↑ 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.
  13. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 23 日 Archived 2014-02-26 at the Wayback Machine