Tau Tauri

Tau Tauri
Location of τ Tauri (circled)
Observation data
Epoch J2000      Equinox ICRS
Constellation Taurus
Right ascension 04h 42m 14.70161s
Declination +22° 57′ 24.9214″
Apparent magnitude (V) 4.27
Characteristics
Spectral type B3V + ? + A0V–A2V + A1V
U−B color index -0.57
B−V color index -0.14
Astrometry
Radial velocity (Rv)+14.60 km/s
Proper motion (μ) RA: -2.89 mas/yr
Dec.: -21.86 mas/yr
Parallax (π)8.19±0.88 mas
Distanceapprox. 400 ly
(approx. 120 pc)
Absolute magnitude (MV)-1.15
Orbit
PrimaryAa
Period (P)2.956549±0.000002 d
Semi-major axis (a)≤ 0.01455 AU
Eccentricity (e)0.051±0.019
Periastron epoch (T)2,436,424.207±0.009 JD
Argument of periastron (ω)
(secondary)		126.7±21.8°
Semi-amplitude (K1)
(primary)		53.6±1.0 km/s
Details
Aa
Mass6.4 M☉
Luminosity1,472 L☉
Surface gravity (log g)2.60 cgs
Temperature18,700 K
Metallicity [Fe/H]-0.51 dex
Rotational velocity (v sin i)115 km/s
Other designations
Gaja, τ Tau, 94 Tauri, BD+22°739, FK5 174, GC 5716, HD 29763, HIP 21881, HR 1497, SAO 76721, CCDM J04422+2257AB, WDS J04422+2257A, GSC 01830-02129
Database references
SIMBADdata

Tau Tauri, also named Gaja, is a quadruple star system in the constellation Taurus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.33. The distance to this system is approximately about 400 light years based on parallax. The system is moving further from the Earth with a heliocentric radial velocity of +14.6 km/s, and it is a member of the Taurion OB association, located between Orion and Taurus. It is located 0.7 degree north of the ecliptic, and thus is subject to lunar occultations.

The blue-white hued primary, component Aa, is a B-type main-sequence star with a stellar classification of B3V. It was found to be a close spectroscopic binary in 1903 by American astronomers Edwin B. Frost and Walter S. Adams. The pair have an orbital period of 2.96 days and eccentricity of 0.05. A second companion, white-hued component Ab, has magnitude 6.97 and angular separation 0.2" from the primary in a 58-year orbit. This is a probably A-type main-sequence star with a class of A0V–A2V. The more distant component B is a type A1V star with magnitude 7.2 and separation 62.8".

Nomenclature

Tau Tauri, Latinized from τ Tauri, is the star's Bayer designation. The term gaja(h) (Sanskrit: गज) means elephant, and is the name of a constellation from Bali (Indonesia) corresponding to Taurus, attested in the cultural calendar called Palelintangan. The IAU Working Group on Star Names approved the name Gaja for Tau Tauri Aa (in the elephant's tusk) on 22 February 2026.

See also

References

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  2. 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. S2CID 119257644. Vizier catalog entry
  3. 1 2 Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  4. 1 2 3 Richichi, A.; et al. (June 1994). "New binary stars discovered by lunar occultations". Astronomy and Astrophysics. 286: 829–837. Bibcode:1994A&A...286..829R.
  5. 1 2 3 4 Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976. Vizier catalog entry
  6. 1 2 Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  7. 1 2 Wilson, R. E. (1953). General Catalogue of Stellar Radial Velocities. Papers of the Mount Wilson Observatory. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. LCCN 54001336. OCLC 1847567.
  8. 1 2 Petrie, R. M.; Ebbighausen, E. G. (1961). "The spectroscopic binary Boss 1107". Publications of the Dominion Astrophysical Observatory Victoria. 11: 385–394. Bibcode:1961PDAO...11..385P.
  9. ↑ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873. Vizier catalog entry
  10. 1 2 Hohle, M.M.; Neuhäuser, R.; Schutz, B.F. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. S2CID 111387483. Vizier catalog entry
  11. 1 2 Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014. S2CID 53480665.
  12. ↑ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (2002). "Rotational Velocities of B Stars". The Astrophysical Journal. 573 (1): 359–365. Bibcode:2002ApJ...573..359A. doi:10.1086/340590.
  13. ↑ "tau Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-18.{{cite web}}: CS1 maint: postscript (link)
  14. 1 2 "IAU Catalog of Star Names". Retrieved 22 February 2026.
  15. ↑ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Vizier catalog entry
  16. ↑ Bouy, H.; Alves, J. (December 2015). "Cosmography of OB stars in the solar neighbourhood". Astronomy & Astrophysics. 584: 13. Bibcode:2015A&A...584A..26B. doi:10.1051/0004-6361/201527058. A26.
  17. ↑ Malkov, O. Yu.; Tamazian, V. S.; Docobo, J. A.; Chulkov, D. A. (2012). "Dynamical masses of a selected sample of orbital binaries". Astronomy & Astrophysics. 546: A69. Bibcode:2012A&A...546A..69M. doi:10.1051/0004-6361/201219774. Vizier catalog entry
  18. ↑ "Gaja (गज)". All Skies Encyclopaedia. IAU Working Group on Star Names. Retrieved 22 February 2026.