31 Persei
Star in the constellation Perseus
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31 Persei is a single[13] star in the northern constellation of Perseus. It is visible to the naked eye as a dim, blue-white hued point of light with an apparent visual magnitude of 5.05.[2] This star is located around 172 parsecs (560 ly) away from the Sun,[14] and it is drifting closer with a radial velocity of −1.6 km/s.[5] It is likely a member of the Alpha Persei Cluster.[15]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 03h 19m 07.63796s[1] |
| Declination | 50° 05′ 41.8724″[1] |
| Apparent magnitude (V) | 5.05[2] |
| Characteristics | |
| Spectral type | B5V[3] |
| U−B color index | −0.53[4] |
| B−V color index | −0.06[4] |
| Astrometry | |
| Radial velocity (Rv) | −1.60[5] km/s |
| Proper motion (μ) | RA: +23.580[1] mas/yr Dec.: −23.322[1] mas/yr |
| Parallax (π) | 5.8399±0.1792 mas[1] |
| Distance | 560 ± 20 ly (171 ± 5 pc) |
| Absolute magnitude (MV) | −1.44[6] |
| Details | |
| Mass | 4.647[7] M☉ |
| Radius | 3.4[8] R☉ |
| Luminosity | 950[6] L☉ |
| Temperature | 15,301[6] K |
| Metallicity [Fe/H] | 0.00[9] dex |
| Rotational velocity (v sin i) | 260[10] km/s |
| Age | 234[11] Myr |
| Other designations | |
| 31 Per, BD+49°902, GC 3945, HD 20418, HIP 15444, HR 989, SAO 38714[12] | |
| Database references | |
| SIMBAD | data |
This object is a massive B-type main-sequence star with a stellar classification of B5V[3] and it is currently generating energy through hydrogen fusion at its core. It is around 234[9] million years old and is spinning rapidly with a projected rotational velocity of 260 km/s.[10] The star has 4.6[7] times the mass of the Sun and about 3.4[8] times the radius of the Sun. It is radiating 950[6] times the luminosity of the Sun from its photosphere at an effective temperature of 15,301 K.[6]