 The position of Pollux within the Gemini Constellation. |
|
| Observation data Epoch J2000 |
|
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 45m 19.4s |
| Declination | +28° 01' 35" |
| Apparent magnitude (V) | 1.15 |
| Characteristics | |
| Spectral type | K0 IIIb |
| U-B color index | 0.86 |
| B-V color index | 1.00 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | +3.3 km/s |
| Proper motion (μ) | RA: −625.69 mas/yr Dec.: −45.95 mas/yr |
| Parallax (π) | 96.74 ± 0.87 mas |
| Distance | 33.7 ± 0.3 ly (10.34 ± 0.09 pc) |
| Absolute magnitude (MV) | 1.09 |
| Details | |
| Mass | 1.86 M☉ |
| Radius | 8.0 R☉ |
| Luminosity | 32 |
| Temperature | 4,865 K |
| Metallicity | 90% Sun |
| Rotation | 38 days |
| Age | ? years |
| Other designations | |
| Database references | |
| SIMBAD | data |
Pollux (β Gem / β Geminorum / Beta Geminorum) is one of the brightest stars in the constellation Gemini and one of the brightest in the nighttime sky. Although it has the Bayer designation "beta", it is actually brighter than Alpha Geminorum (Castor). The name Pollux is traditionally thought by some people to carry the meaning "Much Wine", since astrologers associate Pollux with prosperity and celebration with wine. Actually the name Pollux refers specifically to Pollux, one of the twin sons of Zeus and Leda. The star also has the Arabic name Al-Ras al-Tau'am al-Mu'akhar,(الرأس التؤام المؤخر) literally "The Head of the Second Twin". The Chinese recognized Pollux as Yang, which is, according to the Chinese, one of the two fundamental principles upon which all things depend.
Castor and Pollux are the two "heavenly twin" stars giving the constellation Gemini (Latin, "twins") its name. Ironically the two are nothing alike. Castor is a hot white sextuple star system, while Pollux is a single cooler yellow-orange giant .
Castor and Pollux together correspond to the Nakshatra Punarvasu in Hindu astronomy.
Pollux is also the first star visible from earth which is known to have an extrasolar planet in orbit.
Planetary system
| Companion (In order from star) |
Mass (MJ) |
Orbital period (days) |
Semimajor axis (AU) |
Eccentricity |
|---|---|---|---|---|
| b | 2.3 ± 0.45 | 589.64 ± 0.81 | 1.64 ± 0.27 | 0.02 ± 0.03 |
See also
References
- Hatzes et al. (1993). "Long-period radial velocity variations in three K giants". The Astrophysical Journal 413: 339-348.
- Hatzes et al. (2006). "Confirmation of the planet hypothesis for the long-period radial velocity variations of β Geminorum". Astronomy and Astrophysics 457: 335-341.
- Reffert et al. (2006). "Precise Radial Velocities of Giant Stars. II. Pollux and Its Planetary Companion". The Astrophysical Journal 652: 661-665.
External links
- Beta Gem. ARICNS. Retrieved on November 21, 2005.
- Pollux. SolStation. Retrieved on November 21, 2005.
- Extrasolar planet confirmed around β Geminorum
- Precise Radial Velocities of Giant Stars II. Pollux and its Planetary Companion
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