Tau Leonis
Tau Leonis (τ Leo) is a star in the zodiac constellation of Leo. Because it is located near the ecliptic, it is subject to occultations by the Moon.[8] It has an apparent visual magnitude of 5.00,[2] which is bright enough to be seen with the naked eye. The distance to this star, as estimated using parallax measurements,[1] is 560 light years. It is moving closer to the Sun with a radial velocity of −9 km/s.[4]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Leo |
| Right ascension | 11h 27m 56.23976s[1] |
| Declination | +02° 51′ 22.5609″[1] |
| Apparent magnitude (V) | 5.00[2] |
| Characteristics | |
| Spectral type | G8- IIIa[3] |
| U−B color index | +0.80[2] |
| B−V color index | +1.005[2] |
| Astrometry | |
| Radial velocity (Rv) | −8.90[4] km/s |
| Proper motion (μ) | RA: +16.89[1] mas/yr Dec.: −9.81[1] mas/yr |
| Parallax (π) | 5.80 ± 0.33[1] mas |
| Distance | 560 ± 30 ly (172 ± 10 pc) |
| Absolute magnitude (MV) | −1.12±0.124[5] |
| Details | |
| Mass | 3.90±0.19[6] M☉ |
| Radius | 25.14±1.55[6] R☉ |
| Luminosity | 329.6±39.6[6] L☉ |
| Surface gravity (log g) | 2.25±0.05[6] cgs |
| Temperature | 4,910±33[6] K |
| Metallicity [Fe/H] | −0.07±0.10[6] dex |
| Age | 190±20[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This G-type giant star has a stellar classification of G8- IIIa[3] and currently resides on the red giant branch. It has about 390% of the Sun's mass. The star is much younger than the Sun, with an age of around 190 million years. As an evolved giant, it has expanded to about 25 times the Sun's radius and radiates 330 times the luminosity of the Sun. The effective temperature of the outer atmosphere is 4,910 K.[6]
References
- 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.
- Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, Bibcode:1986EgUBV........0M.
- Keenan, P.; McNeil, R. (October 1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245–266, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
- Park, Sunkyung; et al. (2013), "Wilson-Bappu Effect: Extended to Surface Gravity", The Astronomical Journal, 146 (4): 73, arXiv:1307.0592, Bibcode:2013AJ....146...73P, doi:10.1088/0004-6256/146/4/73.
- Hekker, S.; Meléndez, J. (2007), "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters", Astronomy and Astrophysics, 475 (3): 1003–1009, arXiv:0709.1145, Bibcode:2007A&A...475.1003H, doi:10.1051/0004-6361:20078233.
- "* tau Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-09-29.
- Richichi, A.; et al. (December 2017), "Further Lunar Occultations from the 2.4 m Thai National Telescope", The Astronomical Journal, 154 (6): 4, Bibcode:2017AJ....154..215R, doi:10.3847/1538-3881/aa9068, 215.