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Created page with ''''Pollux''', also called '''Beta Geminorium''', is an orange giant located in the constellation Gemini 33.7 light years away. Although Pollux has the Bayer designation ...'
'''Pollux''', also called '''Beta Geminorium''', is an orange giant located in the constellation [[Gemini]] 33.7 light years away. Although Pollux has the [[Bayer designation]] of Beta, ([[Castor]] having the Alpha designation) it is actually the brightest star in the constellation. Pollux is the 17th brightest star overall in the night sky with an apparent magnitude of 1.15. In 2006 it was confirmed that Pollux has one known extrasolar planet in orbit.
==Star Name==
The name Pollux is based on the twins Pollux and Castor of [[Greek mythology]], who were the twin sons of [[Zeus]] and Leda. The original name in classical [[Greece]] for Pollux was Πολυδευκής or ''Polydeuces''. [[Ptolemy]] though like to refer to the star using the word ὑπόκιρρος, which described the star as "yellowish" or "reddish", and not as a formal name. In [[Arabic]], the star is called الرأس التؤام المؤخر or ''Al-Ras al-Tau'am al-Mu'akhar'', meaning "The Head of the Second Twin".<ref>http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Gemini*.html</ref>
==The Star==
Pollux is a orange-red giant with a spectral classification of K0 IIIb. The [[star]] is 8.8 times the diameter of our [[Sun]]. However like all giants, it has a low mass, being only 1.7 times as massive as our own star.<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000ApJ...528..885A&db_key=AST&data_type=HTML&format=&high=44a287269c18839</ref> Pollux is 32 times as visually luminous as our Sun, with a total luminosity 46 times as great when accounting for the [[infrared]]. As a cooler class K giant, Pollux has a surface temperature of around 4770 K.<ref>http://stars.astro.illinois.edu/sow/pollux.html</ref> The star has a [[metallicity]] (abundance of elements heavier then [[hydrogen]] and [[helium]]) between 85 and 155 percent of that of our Sun, based on the abundance of iron measured.<ref>http://www.solstation.com/stars2/pollux.htm</ref>
Due to Pollux's high mass estimates, and the fact it has evolved out of the main sequence, the star is likely significantly younger then the age of our own Sun (4.6 billion years). The star itself has used up all its core hydrogen fuel and has shifted to fusing helium in its core to [[carbon]] and [[oxygen]]. Eventually, after a few hundred million years, the star will lose much of its mass. This lose of mass will puff out from the star as a planetary nebula, consisting mostly of hydrogen and helium, with some heavier elements (such as carbon and oxygen). Once this occurs, the resultant left over star will be a [[white dwarf]].
==Planetary System==
Pollux has one confirmed extrasoloar planet in orbit. The planet, unofficially called "Polydeuces" was first detected in 1993, but was not confirmed until June 16, 2006. Polydeuces is a [[Jupiter]] class [[gas giant]] with a minimum mass of 2.3 times of Jupiter. The planet orbits Pollux with an average distance of 1.64 AU and takes around 1.6 years to complete.<ref>http://lanl.arxiv.org/abs/astro-ph/0606517</ref>
For an [[terrestrial planet|Earth-like]] world to have liquid [[water]] on its surface, it would need to be centered around 5.7 Au from Pollux, equivalent to Jupiter's orbit of the Sun.
[[Category:Astronomy]]
==References==
{{reflist}}
==Links==
*[http://exoplanet.eu/ Extrasolar Planets Encyclopaedia]
*[http://exoplanets.org/ ExoPlanets]
*[http://stars.astro.illinois.edu/sow/pp.html The Planet Project]
==Star Name==
The name Pollux is based on the twins Pollux and Castor of [[Greek mythology]], who were the twin sons of [[Zeus]] and Leda. The original name in classical [[Greece]] for Pollux was Πολυδευκής or ''Polydeuces''. [[Ptolemy]] though like to refer to the star using the word ὑπόκιρρος, which described the star as "yellowish" or "reddish", and not as a formal name. In [[Arabic]], the star is called الرأس التؤام المؤخر or ''Al-Ras al-Tau'am al-Mu'akhar'', meaning "The Head of the Second Twin".<ref>http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Gemini*.html</ref>
==The Star==
Pollux is a orange-red giant with a spectral classification of K0 IIIb. The [[star]] is 8.8 times the diameter of our [[Sun]]. However like all giants, it has a low mass, being only 1.7 times as massive as our own star.<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000ApJ...528..885A&db_key=AST&data_type=HTML&format=&high=44a287269c18839</ref> Pollux is 32 times as visually luminous as our Sun, with a total luminosity 46 times as great when accounting for the [[infrared]]. As a cooler class K giant, Pollux has a surface temperature of around 4770 K.<ref>http://stars.astro.illinois.edu/sow/pollux.html</ref> The star has a [[metallicity]] (abundance of elements heavier then [[hydrogen]] and [[helium]]) between 85 and 155 percent of that of our Sun, based on the abundance of iron measured.<ref>http://www.solstation.com/stars2/pollux.htm</ref>
Due to Pollux's high mass estimates, and the fact it has evolved out of the main sequence, the star is likely significantly younger then the age of our own Sun (4.6 billion years). The star itself has used up all its core hydrogen fuel and has shifted to fusing helium in its core to [[carbon]] and [[oxygen]]. Eventually, after a few hundred million years, the star will lose much of its mass. This lose of mass will puff out from the star as a planetary nebula, consisting mostly of hydrogen and helium, with some heavier elements (such as carbon and oxygen). Once this occurs, the resultant left over star will be a [[white dwarf]].
==Planetary System==
Pollux has one confirmed extrasoloar planet in orbit. The planet, unofficially called "Polydeuces" was first detected in 1993, but was not confirmed until June 16, 2006. Polydeuces is a [[Jupiter]] class [[gas giant]] with a minimum mass of 2.3 times of Jupiter. The planet orbits Pollux with an average distance of 1.64 AU and takes around 1.6 years to complete.<ref>http://lanl.arxiv.org/abs/astro-ph/0606517</ref>
For an [[terrestrial planet|Earth-like]] world to have liquid [[water]] on its surface, it would need to be centered around 5.7 Au from Pollux, equivalent to Jupiter's orbit of the Sun.
[[Category:Astronomy]]
==References==
{{reflist}}
==Links==
*[http://exoplanet.eu/ Extrasolar Planets Encyclopaedia]
*[http://exoplanets.org/ ExoPlanets]
*[http://stars.astro.illinois.edu/sow/pp.html The Planet Project]