File:Gemini_constellation_map.svg · Wikimedia Commons · See Wikimedia Commons
Castor
Sign in to saveAlso known as Alpha Geminorum, 66 Geminorum, HIP 36850, HIC 36850, 66 Gem, α Geminorum, α Gem, HD 60179
star in the constellation Gemini
Castor is a bright star located in the constellation Gemini, one of the zodiac constellations visible in the night sky. It matters to astronomy because it is actually a complex multiple star system rather than a single star, making it scientifically valuable for understanding stellar properties and interactions.
AI-generated from the Wikipedia summary — may contain errors.
Wikidata facts
- Distance from Earth
- 49.8
- Radius
- 2.31
- Mass
- 2.151
- Image
- Gemini constellation map.png
Show 16 more facts
- spectral class
- A1.5IV+
- catalog code
- GC 10120
- apparent magnitude
- 1.64
- right ascension
- 113.649471640
- parallax
- 64.12
- absolute magnitude
- 1.332
- luminosity
- 3014
- declination
- 31.888282216
- radial velocity
- 5.40
- Commons category
- Castor (star)
- right ascension component of proper motion
- -165
- declination component of proper motion
- -110
- stellar rotational velocity
- 20
- effective temperature
- 9900
- metallicity
- 0.1
- surface gravity
- 10000
Sources (2)
via Wikidata · CC0
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Article
Castor is the second-brightest object in the zodiac constellation of Gemini. It has the Bayer designation α Geminorum, which is Latinised to Alpha Geminorum and abbreviated Alpha Gem or α Gem. With an apparent visual magnitude of 1.58, it is one of the brightest stars in the night sky. Castor appears singular to the naked eye, but it is actually a sextuple star system organized into three binary pairs. Although it is the 'α' (alpha) member of the constellation, it is half a magnitude fainter than 'β' (beta) Geminorum, Pollux.
Stellar system