Sigma Octanus system

The Sigma Octanus system is a planetary system with at least four planets orbiting a binary star, and is identified as a region in FLEETCOM Sector Three. The system is home to the human colony world of Sigma Octanus IV, which had a population of over 17 million people prior to the Battle of Sigma Octanus IV.

During the Battle of Sigma Octanus IV, Captain Jacob Keyes performed the famous Keyes Loop in the system. In addition, John-117 and the Blue Team found a strange Forerunner artifact in Côte d'Azur Museum of Natural History on Sigma Octanus IV while the Covenant tried to retrieve it. The system remained under UNSC control after the battle which ended in a rare UNSC victory.

Trivia

 * While there is in fact no actual star with the designation "Sigma Octanus", there is one named "Sigma Octantis", a slight spelling change, located 270 light years from the Sol system. However, it is unlikely to be the same system for a number of reasons. The real-world Sigma Octantis is classified as a F0 III-type giant instead of a binary star. In addition, it would make Sigma Octanus the astronomically furthest known UNSC colony, significantly further than the Outer Colony system 23 Librae which was considered to be "behind enemy lines" by 2535. Furthermore, the traveled from the system to Reach in less than a month. Traveling over 250 light years in such timeframe would be difficult with human slipspace velocities.
 * While the system is implied in Halo: The Fall of Reach to contain binary stars, one of them (likely the primary) is apparently known as Sigma Octanus as it is later stated that "light from Sigma Octanus" reflected off the debris of the battle in the system.

List of appearances

 * Halo: The Fall of Reach
 * Halo: Fall of Reach
 * Covenant