Tau Aurigae

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Tau Aurigae
Diagram showing star positions and boundaries of the Auriga constellation and its surroundings
Cercle rouge 100%.svg

The location of τ Aurigae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension 05h 49m 10.43826s[1]
Declination +39° 10′ 51.8627″[1]
Apparent magnitude (V) 4.505[2]
Spectral type G8 III[3]
U−B color index +0.692[2]
B−V color index +0.956[2]
R−I color index 0.49
Radial velocity (Rv) –19.32 ± 0.19[4] km/s
Proper motion (μ) RA: –28.30[1] mas/yr
Dec.: –24.97[1] mas/yr
Parallax (π) 15.77 ± 0.20[1] mas
Distance 207 ± 3 ly
(63.4 ± 0.8 pc)
Radius 11[4] R
Luminosity 63[4] L
Surface gravity (log g) 2.7[4] cgs
Temperature 4,887[4] K
Metallicity [Fe/H] –0.27[4] dex
Rotational velocity (v sin i) 3.8[4] km/s
Other designations
29 Aurigae, BD+39 1418, HD 38656, HIP 27483, HR 1995, SAO 58465.[5]
Database references

Tau Aurigae (τ Aur, τ Aurigae) is the Bayer designation for a star in the constellation Auriga. It is visible to the naked eye with an apparent visual magnitude of 4.505,[2] and is approximately 207 light-years (63 parsecs) distant from Earth. This is an evolved giant star with a stellar classification of G8 III.[3] It has expanded to 11 times the radius of the Sun and shines with 63 times the Sun's luminosity. This energy is radiated into outer space from the outer atmosphere at an effective temperature of 4,887.[4] This heat gives it the yellow-hued glow of a G-type star.[6]


  1. ^ a b c d e van Leeuwen, Floor (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752v1Freely accessible, doi:10.1051/0004-6361:20078357.  Note: see VizieR catalogue I/311.
  2. ^ a b c d Oja, T. (August 1986), "UBV photometry of stars whose positions are accurately known. III", Astronomy and Astrophysics Supplement Series, 65 (2): 405–409, Bibcode:1986A&AS...65..405O. 
  3. ^ a b Roman, Nancy G. (July 1952), "The Spectra of the Bright Stars of Types F5-K5", Astrophysical Journal, 116: 122, Bibcode:1952ApJ...116..122R, doi:10.1086/145598. 
  4. ^ a b c d e f g h 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. ^ "tau Aur -- Star in double system", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-08-20. 
  6. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16. 

External links[edit]