Astronomy:Tau Aurigae
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Auriga[1] |
| Right ascension | 05h 49m 10.438s[2] |
| Declination | +39° 10′ 51.86″[2] |
| Apparent magnitude (V) | 4.505[3] |
| Characteristics | |
| Spectral type | G8IIIb Fe-1[4] |
| U−B color index | +0.692[3] |
| B−V color index | +0.956[3] |
| R−I color index | 0.49[citation needed] |
| Astrometry | |
| Radial velocity (Rv) | −19.32±0.19[5] km/s |
| Proper motion (μ) | RA: −28.265[2] mas/yr Dec.: −25.064[2] mas/yr |
| Parallax (π) | 15.5486 ± 0.1215[2] mas |
| Distance | 210 ± 2 ly (64.3 ± 0.5 pc) |
| Absolute magnitude (MV) | 0.50[1] |
| Details | |
| Mass | 2.55[6] M☉ |
| Radius | 11[5] R☉ |
| Luminosity | 63[5] L☉ |
| Surface gravity (log g) | 2.7[5] cgs |
| Temperature | 4,887[5] K |
| Metallicity [Fe/H] | −0.27[5] dex |
| Rotational velocity (v sin i) | 3.8[5] km/s |
| Age | 660 to 890[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Tau Aurigae is a star in the northern constellation Auriga. Its name is a Bayer designation that is Latinized from τ Aurigae, and abbreviated Tau Aur or τ Aur. This star is visible to the naked eye with an apparent visual magnitude of 4.5[3] and is positioned about a half degree west of the brighter star Nu Aurigae.[8] Based on parallax measurements, it is approximately 210 light-years (64 parsecs) distant from Earth. The star is drifting closer to the Sun with a radial velocity of −19 km/s.[5]
Tau Aurigae is an evolved giant star with a stellar classification of G8IIIb Fe-1,[4] which indicates it has exhausted the supply of hydrogen at its core and expanded off the main sequence of Sun-like stars. The 'Fe-1' notation indicates that the stellar spectrum has anomalously weak lines of iron. This star is an estimated 660–890 million years old and is spinning with a projected rotational velocity of 3.8 km/s.[5] With 2.6[6] times the mass of the Sun, it has 11 times the Sun's radius and shines with 63 times the Sun's luminosity. This energy is radiated into outer space from the photosphere at an effective temperature of 4,887 K.[5] This heat gives it the yellow-hued glow of a G-type star.[9]
References
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940. Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 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.
- ↑ 4.0 4.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", The Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 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, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ 6.0 6.1 6.2 Feuillet, Diane K. et al. (2016), "Determining Ages of APOGEE Giants with Known Distances", The Astrophysical Journal 817 (1): 40, doi:10.3847/0004-637x/817/1/40, Bibcode: 2016ApJ...817...40F.
- ↑ "tau Aur". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tau+Aur.
- ↑ Sinnott, Roger W.; Perryman, Michael A. C. (1997), Millennium Star Atlas, 1, Sky Publishing Corporation and the European Space Agency, p. 113, ISBN 0-933346-84-0.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16.
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