Pollux (star)
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Gemini |
| Pronunciation | /ˈpɒləks/ |
| Right ascension | 07h 45m 18.94987s |
| Declination | +28° 01′ 34.3160″ |
| Apparent magnitude (V) | 1.14 |
| Characteristics | |
| Evolutionary stage | Red clump |
| Spectral type | K0 III |
| U−B color index | +0.86 |
| B−V color index | +1.00 |
| V−R color index | +0.75 |
| R−I color index | +0.50 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | +3.23 km/s |
| Proper motion (μ) | RA: −626.55 mas/yr Dec.: −45.80 mas/yr |
| Parallax (π) | 96.54±0.27 mas |
| Distance | 33.78 ± 0.09 ly (10.36 ± 0.03 pc) |
| Absolute magnitude (MV) | +1.08±0.02 |
| Details | |
| Mass | 1.91±0.09 M☉ |
| Radius | 8.97±0.03 R☉ |
| Luminosity | 38.4±0.3 L☉ |
| Surface gravity (log g) | 2.55±0.03 cgs |
| Temperature | 4,810±14 K |
| Metallicity [Fe/H] | –0.07 to +0.19 dex |
| Rotation | 660±15 d |
| Rotational velocity (v sin i) | 2.8 km/s |
| Age | 1.19±0.3 (0.9 – 1.7) Gyr |
| Other designations | |
| β Geminorum, 78 Geminorum, BD+28°1463, GJ 286, HD 62509, HIP 37826, HR 2990, SAO 79666, LFT 548, LHS 1945, LTT 12065 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
Pollux is the brightest star in the constellation of Gemini. It has the Bayer designation β Geminorum, which is Latinised to Beta Geminorum and abbreviated Beta Gem or β Gem. This is an orange-hued, evolved red giant located at a distance of 34 light-years, making it the closest red giant (and giant star) to the Sun. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. In 2006 an exoplanet (designated Pollux b or β Geminorum b, later named Thestias) was announced to be orbiting it.