Urs

The Urs system, formally known as the Urs-Fied-Joori system, is a triple star system most notable as the home system of the Sangheili species. The system consists of the A-type dwarf star Urs (Urs A), its smaller F-type companion Fied (Urs B), and the red dwarf Joori (Urs C), which orbits Urs at a distance of several dozen AU from the main pair. Most planets in the system, including the fourth, Sanghelios, orbit Urs, though a small number of planets orbit the distant Joori.

Located in the Orion Arm approximately 3,500 light-years trailing from Sol, Urs is considered by many to be one of the closest things the Holy Ecumene has to a fixed physical core. As the hub and epicenter of the Sunlit Worlds, Urs is one of the most populated and trafficked systems in the Covenant, with several colonized planets and moons along with numerous space habitats and stations. Aside from Sanghelios, two other planets in the system are fully habitable by the Sangheili, which has led to some speculation at possible Forerunner ecoforming or an intervention by an even earlier civilization. While not a full-fledged nebula, the interstellar medium within several dozen light-years around the Urs system is relatively dense. This made early slipspace navigation relatively easy for the Sangheili, as the ISM provided clear navigation routes and ample traction for the early blinker drives to drag ships along.

History
The system's trinary makeup had a notable effect on the culture and mythology of the Sangheili. Its three stars and many planets would often be cast as religious and mythological figures, with Urs frequently being a primary sun deity, Fied his consort, and Joori a wayward or banished relative, often a form of trickster god. By the time Forerunner worship became the mainstream religion on Sanghelios, the old sun-faiths were already waning or all but dead, but their legacy lived on in Sangheili culture and language. For example, the sun-deities and mythic figures named after the three stars and the planets orbiting them remained as the subject of many proverbs and greetings.

The planets around Joori served as a target for early Sangheili colonization efforts. After contact with the system at large was lost in the Skyfall, the Joorian colonies developed a distinct cultural character from that of Sanghelios and would only be re-contacted centuries later.