Soell

The Soell system, also known as Iota Horologii, was a strategically-important star system of nine planets located in the Enuma Sector of the Orion-Eridanus Supersector.

In the waning years of the Diluvial War, it was chosen as the site where Halo Installation 04 would be deployed, which was activated with the other Halos to wipe out all sapient life in the Milky Way galaxy. It was discovered by the crew of the in September 2552, who were pursued from Reach by the Fleet of Particular Justice. In the ensuring battle, Alpha Halo was destroyed by John-117.

In the aftermath, the Covenant established a large presence in the system in order to research the various relics that survived the Halo's detonation. The UNSC and the Concord of Reconciliation captured the system some time after the Human-Covenant War, where the two governments considered it a joint-operations area.

Known locations

 * Soell V
 * Threshold — Super-Jovian gas giant. Houses an array of atmospheric gas extraction and refinery facilities, all of which have not been explored.
 * Halo Installation 04 — Due to potential continued Flood contamination, the debris field remains an exclusion zone enforced by the UNSC and Concord fleets patrolling the area. Scientific incursions continue to be made to the segments of the broken ring as well as various other Forerunner facilities around Threshold, though precautions are extreme.
 * Basis — Housed a small heretic camp that went undetected until nearly a year later.
 * Vector — One of Threshold's smaller and further-out moons.
 * Keyes Station — A former Covenant outpost established in a secondary Forerunner facility on Vector. Used as an impromptu base by the UNSC and the Schismatics after the system's capture, it was shortly later formally established as Keyes Station.