Tau2 Arietis
- For other star systems with this Bayer designation, see Tau Arietis.
| |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Aries |
| Right ascension | 03h 22m 45.24006s[1] |
| Declination | +20° 44′ 31.4382″[1] |
| Apparent magnitude (V) | +5.09[2] |
| Characteristics | |
| Spectral type | K3 III[3] |
| U−B color index | +1.27[2] |
| B−V color index | 1.238[4] |
| Astrometry | |
| Radial velocity (Rv) | +2.45 ± 0.24[4] km/s |
| Proper motion (μ) | RA: –51.59[1] mas/yr Dec.: –16.06[1] mas/yr |
| Parallax (π) | 10.27 ± 0.60[1] mas |
| Distance | 320 ± 20 ly (97 ± 6 pc) |
| Details | |
| Radius | 19[4] R☉ |
| Luminosity | 120[4] L☉ |
| Surface gravity (log g) | 2.1[4] cgs |
| Temperature | 4,406[4] K |
| Metallicity [Fe/H] | +0.02[4] dex |
| Rotational velocity (v sin i) | 3.4[4] km/s |
| Other designations | |
Tau2 Arietis (τ2 Ari, τ2 Arietis) is the Bayer designation for a binary star[6] in the northern constellation on Aries. The combined apparent visual magnitude of this system is +5.09,[2] which is bright enough to be seen with the naked eye. With an annual parallax shift of 10.27 mas,[1] it is located at a distance of approximately 320 light-years (98 parsecs) from Earth, give or take a 20 light-year margin of error. At this distance the brightness of the star is diminished by 0.18 in magnitude because of extinction from interstellar gas and dust.[7]
The primary component is an evolved giant star with a stellar classification of K3 III.[8] It has expanded to 19 times the radius of the Sun, from which it is radiating 120 times the Sun's luminosity.[4] This energy is being emitted into outer space from the outer atmosphere at an effective temperature of 4,406 K,[4] giving it the cool orange glow of a K-type star. At an angular separation of 0.53 arcseconds is a magnitude 8.50 companion.[6]
References
- 1 2 3 4 5 6 van Leeuwen, F. (November 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. - 1 2 3 Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133: 475, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475.
- ↑ Cenarro, A. J.; et al. (January 2007), "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters", Monthly Notices of the Royal Astronomical Society, 374 (2): 664–690, arXiv:astro-ph/0611618, Bibcode:2007MNRAS.374..664C, doi:10.1111/j.1365-2966.2006.11196.x.
- 1 2 3 4 5 6 7 8 9 10 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.
- ↑ "63 Ari -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-18.
- 1 2 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.
- ↑ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272
- ↑ 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.