Castor (also known as Alpha Geminorum) is a star system, a multiple star in Federation space in the Beta Quadrant. Castor's multiple system consists of six stars, including Castor B, which is orbited by Castus. The Castor system is visible from Earth in the Sol system, 49 light-years distant, as part of Human history's Gemini constellation. (TOS video game: 25th Anniversary; ST reference: Star Charts)