Castor (star)
Castor (α Gem, α Geminorum, Alpha Geminorum) is the second brightest star in the constellation Gemini and one of the brightest stars in the night sky. Although it has the Bayer designation "alpha", it is actually fainter than Beta Geminorum (Pollux). Castor is 49.8 light years away from Earth.
Read more about Castor (star): Physical Characteristics, The Castor System, Etymology and Culture