Omicron Tauri


Omicron Tauri
Taurus constellation map.svg
Red circle.svg
Location of ο Tauri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Taurus
Right ascension 03h 24m 48.79146s[1]
Declination +09° 01′ 43.9941″[1]
Apparent magnitude (V) 3.61[2]
Spectral type G6 III[3]
B−V color index +0.887±0.019[2]
Radial velocity (Rv)−19.79±0.06[1] km/s
Proper motion (μ) RA: –59.776[1] mas/yr
Dec.: –78.579[1] mas/yr
Parallax (π)17.1066 ± 0.3775[1] mas
Distance191 ± 4 ly
(58 ± 1 pc)
Absolute magnitude (MV)−0.45[4]
Period (P)1654.9 d
Eccentricity (e)0.26
Periastron epoch (T)2429974.34 JD
Argument of periastron (ω)
Semi-amplitude (K1)
4.4 km/s
ο Tauri A
Mass3.01[4] M
[1] R
Luminosity149.4±3.7[1] L
Surface gravity (log g)2.52[4] cgs
Temperature5,180[4] K
Metallicity [Fe/H]–0.12[4] dex
Rotational velocity (v sin i)25 ± 2[6] km/s
Age380[4] Myr
Other designations
ο Tau, 1 Tauri, BD+08° 511, FK5 121, HD 21120, HIP 15900, HR 1030, SAO 111172[7]
Database references

ο Tauri, Latinized as Omicron Tauri, is a binary star system in the constellation Taurus, near the constellation border with Cetus. It has a yellow hue and is visible to the naked eye with an apparent visual magnitude of 3.61.[2] It is approximately 191 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −20 km/s.[1] This system has the Flamsteed designation 1 Tauri; Omicron Tauri is the Bayer designation.[7]

This is a single-lined spectroscopic binary[5] system with the two components orbiting each other over a period of 4.53 years with an eccentricity of 0.263.[8] The visible component is an aging G-type giant with a stellar classification of G6 III.[3] This star has three[4] times the mass of the Sun and eighteen[1] times the Sun's radius. Based on the latter, interferometry-measured radius, it is rotating once every 533 days.[9] It is radiating 149[1] times the luminosity of the Sun from its photosphere at an effective temperature of 5,180 K.[4]


  1. ^ a b c d e f g h i j k Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c 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.
  3. ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. ^ a b c d e f g h da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105, S2CID 9341088.
  5. ^ a b Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
  6. ^ Nieva, M.-F. (February 2013), "Temperature, gravity, and bolometric correction scales for non-supergiant OB stars", Astronomy & Astrophysics, 550: A26, arXiv:1212.0928, Bibcode:2013A&A...550A..26N, doi:10.1051/0004-6361/201219677, S2CID 119275940.
  7. ^ a b "omi Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-10.
  8. ^ Jackson, E. S.; et al. (May 1957), "The Orbits of the Spectroscopic Binaries Omicron Tauri, Xi Cancri, and Mu Ursae Majories", Astrophysical Journal, 125: 712, Bibcode:1957ApJ...125..712J, doi:10.1086/146345
  9. ^ Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1

External links

  • Kaler, James B. (March 20, 2009), "Omicron Tauri", STARS, retrieved 2019-10-10.