Pollux (β Gem, β Geminorum, Beta Geminorum) is a starn in the northren constellation o Gemini, the Twins. It is an evolved giant star wi an orange hue. At an apparent visual magnitude o 1.1,[2] Pollux is the brichtest starn in the constellation; brichter even than its neighbor Castor (Alpha Geminorum). Parallax measurments made wi the Hipparcos astrometry satellite[13][14] place it at a distance o aboot 33.78 light-year (10.36 parsec) frae Yird[1]. Syne 1943, the spectrum o this starn haes served as ane o the stable anchor pynts bi which ither starns are classified.[15] In 2006, Pollux wis confirmed tae hae an extrasolar planet orbitin it.[7]

Gemini constellation map.svg
The poseetion o Pollux within the constellation o Gemini.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Gemini
Richt ascension 07h 45m 18.94987s[1]
Declination +28° 01′ 34.3160″[1]
Apparent magnitude (V) 1.14[2]
Spectral type K0 III[3]
U−B colour index +0.86[2]
B−V colour index +1.00[2]
Variable teep Suspected
Radial velocity (Rv)+3.23[4] km/s
Proper motion (μ) RA: –626.55[1] mas/yr
Dec.: –45.80[1] mas/yr
Parallax (π)96.54 ± 0.27[1] mas
Distance33.78 ± 0.09 ly
(10.36 ± 0.03 pc)
Absolute magnitude (MV)+1.08 ± 0.02[5]
Mass2.04 ± 0.3[6] M
Radius8.8 ± 0.1[7] R
Luminosity43[8] L
Surface gravity (log g)2.685 ± 0.09[7] cgs
Temperatur4,666 ± 95[7] K
Metallicity [Fe/H]–0.07 to +0.19[7] dex
Rotation558 days[9]
Rotational velocity (v sin i)2.8[10] km/s
Age724[11] Myr
Ither designations
Beta Geminorum, 78 Geminorum, BD+28°1463, GCTP 1826.00, Gliese 286, HD 62509, HIP 37826, HR 2990, LFT 548, LHS 1945, LTT 12065, SAO 79666.[12]
Database references


  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 Unknown parameter |month= ignored (help)
  2. 2.0 2.1 2.2 2.3 Lee, T. A. (1970), "Photometry of high-luminosity M-type stars", Astrophysical Journal, 162: 217, Bibcode:1970ApJ...162..217L, doi:10.1086/150648 Unknown parameter |month= ignored (help)
  3. Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333
  4. Famaey, B.; et al. (2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272 Unknown parameter |month= ignored (help)
  5. Carney, Bruce W.; et al. (2008), "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars", The Astronomical Journal, 135 (3): 892–906, arXiv:0711.4984, Bibcode:2008AJ....135..892C, doi:10.1088/0004-6256/135/3/892 Unknown parameter |month= ignored (help)
  6. Aurière, M.; et al. (2009), "Discovery of a weak magnetic field in the photosphere of the single giant Pollux", Astronomy and Astrophysics, 504 (1): 231–237, arXiv:0907.1423, Bibcode:2009A&A...504..231A, doi:10.1051/0004-6361/200912050 Unknown parameter |month= ignored (help)
  7. 7.0 7.1 7.2 7.3 7.4 Hatzes, A. P.; et al. (2006), "Confirmation of the planet hypothesis for the long-period radial velocity variations of β Geminorum", Astronomy and Astrophysics, 457: 335–341, arXiv:astro-ph/0606517, Bibcode:2006A&A...457..335H, doi:10.1051/0004-6361:20065445
  8. Mallik, Sushma V. (1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M Unknown parameter |month= ignored (help)
  9. Koncewicz, R.; Jordan (2007), "OI line emission in cool stars: calculations using partial redistribution", Monthly Notices of the Royal Astronomical Society, 374 (1): 220–231, Bibcode:2007MNRAS.374..220K, doi:10.1111/j.1365-2966.2006.11130.x Unknown parameter |month= ignored (help); |first4= missing |last4= (help)
  10. Massarotti, Alessandro; et al. (2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209 Unknown parameter |month= ignored (help)
  11. Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (2008), "Stellar parameters and elemental abundances of late-G giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T Unknown parameter |month= ignored (help)
  12. "POLLUX -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-14
  13. Perryman, M. A. C.; Lindegren, L.; Kovalevsky, J.; et al. (1997), "The Hipparcos Catalogue", Astronomy and Astrophysics, 323: L49–L52, Bibcode:1997A&A...323L..49P Unknown parameter |month= ignored (help); Explicit use of et al. in: |last4= (help)
  14. Perryman, Michael (2010), The Making of History's Greatest Star Map, Heidelberg: Springer-Verlag, doi:10.1007/978-3-642-11602-5
  15. Garrison, R. F. (1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society, 25: 1319, Bibcode:1993AAS...183.1710G, retrieved 2012-02-04 Unknown parameter |month= ignored (help)