23 Librae system

23 Librae (23 Lib) is a yellow dwarf star in the constellation Libra, and is about 83.7 light-years from the Sol system. 23 Lib has a mass of 1.05 Suns and a radius of 1.25 Suns.

23 Librae is orbited by at least two planets, Madrigal and Hesiod. Hesiod is the only gas giant orbiting 23 Librae. Madrigal, the only planet in 23 Librae's habitable zone, was a human Outer Colony until the Covenant arrived and glassed the planet in 2528.

History
Madrigal was colonized by humanity, serving as a thriving human colony. It was glassed by the Covenant in 2528.

Survivors of the attack fled to the Trojan asteroids trailing the gas giant Hesiod, farther out-system. There, they joined Insurrectionists in the asteroid colony known as the Rubble. Kig-Yar merchants established trade relations with the humans in the asteroids while the Covenant plotted to raise an army of Unggoy on Hesiod's moon Metisette. Both the Rubble and the Covenant installation on Metisette were destroyed in the Battle of the Rubble and the Battle of Metisette. However, the human inhabitants of the Rubble managed to escape on Habitat Exodus with the help of the and Gray Team while the Covenant forces were completely wiped out by the Midsummer Night.

Known planets

 * Madrigal
 * Hesiod
 * The Rubble
 * Metisette

Trivia
The description of the 23 Librae system in Halo: The Cole Protocol bears several contradictions with real-world astronomical observations of the system. The novel states that Hesiod is the only gas giant in the system. However, as of 2015, at least two gas giants have been discovered orbiting the star. Furthermore, The Cole Protocol establishes that Madrigal—a terrestrial planet—is the only planet in the star's habitable zone. In the real world, the gas giant 23 Librae b was discovered in 1999 as orbiting 23 Librae in its habitable zone.

List of appearances

 * Halo: The Cole Protocol
 * Halo 2: Anniversary
 * ''Terminals
 * Halo: Envoy