Omega1 Tauri


Omega1 Tauri
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Taurus
Right ascension 02h 12m 22.28003s[1]
Declination +30° 18′ 11.0430″[1]
Apparent magnitude (V) +5.51[2]
Spectral type K2 III[2]
B−V color index 1.077[2]
Radial velocity (Rv)+24.75±0.02[2] km/s
Proper motion (μ) RA: −65.05[1] mas/yr
Dec.: −60.50[1] mas/yr
Parallax (π)11.22 ± 0.70[1] mas
Distance290 ± 20 ly
(89 ± 6 pc)
Absolute magnitude (MV)+0.76[2]
Mass1.53[3] M
Radius12[4] R
Luminosity57.5[3] L
Surface gravity (log g)2.5[5] cgs
Temperature4,737±77[3] K
Metallicity [Fe/H]0.12[5] dex
Rotational velocity (v sin i)4.6[4] km/s
Age4.21[3] Gyr
Other designations
ω1 Tau, 43 Tau, BD+19° 672, FK5 1115, HD 26162, HIP 19388, HR 1283, SAO 93785[6]
Database references

Omega1 Tauri is a solitary,[7] orange hued star in the zodiac constellation of Taurus. It is faintly visible to the naked eye with an apparent visual magnitude of +5.51.[2] Based upon an annual parallax shift of 11.22 mas as seen from Earth,[1] it is located about 290 light years from the Sun.

This is an evolved K-type giant star with a stellar classification of K2 III.[2] At the estimated age of 4.2 billion years,[3] it is a red clump star that is generating energy by helium fusion at its core.[5] Omega1 Tauri has about 1.5[3] times the mass of the Sun and has expanded to around 12[4] times the Sun's radius. It is radiating 57.5 times the Sun's luminosity from its photosphere at an effective temperature of 4,737 K.[3] The radial velocity of this star shows no appreciable variation, and for this reason it is used as a radial velocity standard.[2]


  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 e f g h Hekker, S.; et al. (August 2006), "Precise radial velocities of giant stars. I. Stable stars", Astronomy and Astrophysics, 454 (3): 943–949, arXiv:astro-ph/0604502, Bibcode:2006A&A...454..943H, doi:10.1051/0004-6361:20064946, S2CID 119529768.
  3. ^ a b c d e f g Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3), 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
  4. ^ a b c Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  5. ^ a b c Tautvaišienė, G.; et al. (March 2013), "Red clump stars of the Milky Way - laboratories of extra-mixing", Monthly Notices of the Royal Astronomical Society, 430 (1): 621−627, arXiv:1304.4393, Bibcode:2013MNRAS.430..621T, doi:10.1093/mnras/sts663, S2CID 119211439.
  6. ^ "ome01 Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-30.
  7. ^ 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.