Tau Geminorum
star
Tau Geminorum, Latinized from τ Geminorum, is a star in the northern zodiac constellation of Gemini. It has the apparent visual magnitude of +4.42, making it visible to the naked eye under suitably good seeing conditions. This star is close enough to the Earth that its distance can be measured using the parallax technique, which yields a value of roughly 392 light-years (120 parsecs).
It is an evolved giant star of the spectral type K2 III. It has double the mass of the Sun and has expanded to 30 times the Sun's radius. Tau Geminorum is radiating 364 times
as much radiation as the Sun from its expanded outer atmosphere at an effective temperature of 4,583 K, giving it the characteristic orange-hued glow of a K-type star. It appears to be rotating slowly with a projected rotational velocity of 5.8 km/s.
Substellar companion
This star has a brown dwarf companion designated Tau Geminorum b, whose mass is at least 20.6 Jupiter masses. It was discovered in 2004 by Mitchell and colleagues, who also discovered Nu Ophiuchi b at the same time. This brown dwarf takes 305 days (0.84 years) to revolve around Tau Gem.
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This entry incorporates text from “Tau 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.