Castor
66Alp Gem
Castor is a A-type (White) star located in the constellation Gemini. It carries the designation 66Alp Gem.
Located approximately 50.9 light-years from Earth, Castor resides within the broader disk of our Milky Way galaxy.
Castor is classified as a spectral class A star (A-type (White)) on the Harvard spectral classification system.
Castor has an apparent magnitude of +1.58, making it a bright and prominent star that is readily visible to the naked eye. It is one of the more conspicuous stars in its region of the sky. Observers will note its blue-white hue, which corresponds to a B-V color index of +0.034.
Physical Properties
| Spectral Class | Class A — A-type (White) |
| Color Index (B−V) | 0.034 |
Observation
| Apparent Magnitude | +1.58 |
| Absolute Magnitude | 0.62 |
| Distance | 50.9 ly |
| Constellation | Gemini |
Position
| Right Ascension | 7h 34.60m |
| Declination | 31° 53.30′ |
Frequently Asked Questions
What type of star is Castor?
Castor is a Class A — A-type (White) star.
How far is Castor from Earth?
Castor is approximately 50.9 light-years from Earth.
Can you see Castor with the naked eye?
With an apparent magnitude of 1.58, Castor is visible to the naked eye.
What constellation is Castor in?
Castor is located in the constellation Gemini.