| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 14h41m 38.75049s[1] |
| Declination | +08° 09′ 42.3409″[1] |
| Apparent magnitude (V) | 4.86[2] |
| Characteristics | |
| Spectral type | G7 IIIa[3] |
| B−V color index | 0.992±0.038[2] |
| Astrometry | |
| Radial velocity (Rv) | −16.5±1.8[2] km/s |
| Proper motion (μ) | RA: –9.589[1] mas/yr Dec.: +3.906[1] mas/yr |
| Parallax (π) | 6.8757 ± 0.2796 mas[1] |
| Distance | 470 ± 20 ly (145 ± 6 pc) |
| Absolute magnitude (MV) | −1.22[2] |
| Details | |
| Mass | 3.27[4] M☉ |
| Radius | 23.25+0.40 −0.49[1] R☉ |
| Luminosity | 274.9±12.6[1] L☉ |
| Surface gravity (log g) | 2.60[5] cgs |
| Temperature | 4,874+53 −41[1] K |
| Metallicity [Fe/H] | −0.10[5] dex |
| Rotational velocity (v sin i) | 6.5[6] km/s |
| Age | 370[4] Myr |
| Other designations | |
31 Boo, NSV 6769, BD+08°2903, FK5 3163, GC 19789, HD 129312, HIP 71832, HR 5480, SAO 120601[7] | |
| Database references | |
| SIMBAD | data |
31 Boötis is a single[8] star in the northern constellationofBoötes,[7] located 470 light years from the Sun.[1] It is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.86.[2] The object is moving closer to the Earth with a heliocentric radial velocity of −16.5 km/s.[2] It was known to be part of a constellation between Virgo and Boötes named Mons Maenalus, it was also the brightest star in the constellation.
This is an evolved giant star with a stellar classification of G7 IIIa.[3] It is a suspected variable star of unknown type,[9] and is an X-ray source.[10] The star is 370[4] million years old with 3.27[4] times the mass of the Sun. Having exhausted the hydrogen at its core, the star has expanded to 23[1] times the Sun's radius. It is radiating 275[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,874 K.[1]
