1.58
Apparent Mag51
Distance (ly)A1V
Spectral Type10,286
Temperature (K)Castor is the second-brightest star in Gemini despite bearing the Alpha designation. It is a remarkable sextuple star system consisting of three binary pairs.
Stellar Data
Apparent Magnitude1.58
Absolute Magnitude0.59
Distance51 light-years
Spectral TypeA1V
Temperature10,286 K
Luminosity52.4 L☉
Radius2.089 R☉
Mass2.76 M☉
Right Ascension07h 34m 36.0s
Declination+31° 53′ 17.8″
ConstellationGemini
Notable Facts
- Castor is a sextuple star system of three binary pairs
- Despite being Alpha Geminorum, it is fainter than Pollux
- Named after one of the mythological twin brothers