51 Pegasi B

51 Pegasi-B was a planet located in a star system on the fringes of UNSC controlled space, orbiting 51 Pegasi, and was close to 85 Pegasi-194A. It was also home of the small moon of Pegasi Delta.

The Covenant constructed a massive refinery on the planet's moon, Pegasi Delta. Serving as a supply station, the system was to be a Covenant forward staging post for incursions into UNSC space, as Covenant ships would come here and refuel, resupply, and gather to attack the enemy. In 2545, the Spartan-III Beta Company was sent on an attack on this facility during Operation: TORPEDO. Though they successfully destroyed the facility, 296 of the 300 Spartan-IIIs in Beta Company were massacred in a suicidal frontal assault, with the exceptions of Min-B174 after his death in an explosives accident and Adam-B004, who died when the facility exploded. These incidents only left Lucy-B091 and Tom-B292 alive.

51 Pegasi is an actual star, within the constellation Pegasus, with the planet 55 Pegasi b orbiting it. The real life system is 50.1 lightyears from Earth. 51 Pegasi b was the first ever planet discovered orbiting a sun-like star.