Memory Alpha
Memory Alpha

Castor, also known as Alpha Geminorum, was a star system in the Alpha Quadrant. It was a sextenary star system consisting of six stars that together formed three binary star systems. The three systems were Alpha Geminorum A (Castor [the official name for Alpha Geminorum Aa] and Alpha Geminorum Ab), Alpha Geminorum B (Alpha Geminorum Ba and Alpha Geminorum Bb), and Alpha Geminorum C (Alpha Geminorum Ca and Alpha Geminorum Cb).

History[]

In 2257, during the first Federation-Klingon War, the Castor system was occupied by the Klingons. (DIS: "The War Without, The War Within")

Stellar cartography[]

The Castor system was visible from Earth in the constellation Gemini. This system was approximately 49 light years from Sol.

In 2256, the system's location was labeled on the star chart "Alpha/Beta Quadrant Overview" in the ready room aboard the USS Discovery. (DIS: "Magic to Make the Sanest Man Go Mad")

This star system was only mentioned in writing.
Information on this system was derived from the episodes and films, the reference works Star Trek: Star Charts and Stellar Cartography: The Starfleet Reference Library, and real-world sources. The reference works were used extensively in the creation of star charts seen in Star Trek: Discovery, Star Trek: Picard, Star Trek: Strange New Worlds, Star Trek: Prodigy, and Star Trek: Lower Decks. The real-world information added to the article was current as of 2025.

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