51 Pegasi system

The 51 Pegasi system is a planetary system located some 50 light-years from Earth, in the constellation Pegasus. The planetary system is home to the planet 51 Pegasi B and its moon Pegasi Delta, whose rich oceans were mined by the Covenant for deuterium and tritium in 2545. The Covenant refinery complex was the target of a UNSC strike in Operation: TORPEDO, which led to the demise of all but two Beta Company SPARTAN-IIIs.

Trivia
51 Pegasi was the very first main-sequence (Sun-like) star discovered to have a planet in orbit around it.

List of appearances

 * Halo: Ghosts of Onyx