Gamma Geminorum
star in the constellation Gemini
Gamma Geminorum (γ Geminorum, abbreviated Gamma Gem, γ Gem), formally named Alhena , is the third-brightest object in the constellation of Gemini. It has an apparent visual magnitude of 1.9, making it easily visible to the naked eye even in urban regions. Based upon parallax measurements with the Hipparcos satellite, it is located at a distance of roughly 109 light-years (33 parsecs).
Properties
Alhena is an evolving star that is exhausting the supply of hydrogen at its core and has entered the subgiant stage. The spectrum matches a stellar classification of A0 IV. Compared to the Sun it has 3.4 times the mass and six times the radius. It is radiating around 200 times the luminosity of the Sun from its outer envelope at an effective temperature of 9,190 K. This gives it a white hue typical of an A-class star.
Alhena is a spectroscopic binary system with a period of 12.6 years (4,614.51 days) in a highly eccentric Keplerian orbit. The secondary, with 1.4 times the mass of the Sun, is likely a G-type main-sequence star.
Etymology
γ Geminorum (Latinised to Gamma Geminorum) is the star's Bayer designation. The traditional name Alhena is derived from the Arabic الهنعة Al Han'ah, 'the brand' (on the neck of the camel), whilst the alternate name Almeisan is from the Arabic المیسان Al Maisan, 'the shining one.' Al Hanʽah was the name of star association consisting of this star, along with Mu Geminorum (Tejat Posterior), Nu Geminorum, Eta Geminorum (Tejat Prior) and Xi Geminorum (Alzirr).
“Gamma Geminorum” enters the record as star in the constellation Gemini. Crown Archives preserves that source wording while asking what Gamma, Geminorum and star can confirm, complicate or overturn.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 14, 2026. The linked authority identifier is Q14238. VIAF identifies the subject as 4251164539786532240001. None of the 1 selected statements returned an explicit reference.
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This entry incorporates text from “Gamma Geminorum” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.