Pollux (star)

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**Pollux**
Observation data Epoch J2000
The position of Pollux within the Gemini Constellation.
Constellation (pronunciation)	Gemini
Right ascension	07h 45m 19.4s
Declination	+28° 01' 35"
Apparent magnitude (V)	1.15
Characteristics
Spectral type	K0IIIb
U-B color index	0.86
B-V color index	1.00
Variable type	Suspected
Astrometry
Radial velocity (R_v)	+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 (M_V)	1.09
Details
Mass	1.86 M_☉
Radius	8.0 R_☉
Luminosity	32 L_☉
Temperature	4,865 K
Metallicity	90% Sun
Rotation	38 days
Age	? years
Other designations
β Gem, β Geminorum, Beta Geminorum, 78 Geminorum, Gl 286, HR 2990, BD +28°1463, HD 62509, GCTP 1826.00, LHS 1945, LFT 548, LTT 12065, SAO 79666, FK5 295, HIP 37826.
Database references
SIMBAD	data

Pollux (β Gem / β Geminorum /Beta Geminorum) is the brightest star 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).

Castor and Pollux are the two 'heavenly twin' stars giving the constellation Gemini (Latin, 'the twins') its name. Ironically, the two are nothing alike. Castor is a complex sextuple system comprised of hot, bluish-white A-type stars and dim red dwarfs, while Pollux is a single cooler yellow-orange giant.

1 Planetary system
2 Etymology and Cultural Significance
3 See also
4 References
5 External links

[edit] Planetary system

Pollux is one of few stars visible to the naked eye which features an extrasolar planet.

The Pollux (star) system
Companion (in order from star)	Mass (M_J)	Orbital period (days)	Semimajor axis (AU)	Eccentricity
b	2.3 ± 0.45	589.64 ± 0.81	1.64 ± 0.27	0.02 ± 0.03

[edit] Etymology and Cultural Significance

The name Pollux refers specifically to Castor and Pollux, the twin sons of Zeus and Leda. The star also bears Arabic name Al-Ras al-Tau'am al-Mu'akhar,(الرأس التؤام المؤخر), literally, 'The Head of the Second Twin'. Historically, the Chinese recognized Pollux as Yang, which in ancient philosophy was one of the two fundamental principles upon which all things depend. Castor and Pollux together correspond to the Nakshatra Punarvasu in Hindu astronomy.

The name is traditionally thought by some people to carry the meaning 'much wine', since astrologers associate Pollux with prosperity and celebration with wine.