The Ilum system encompassed a star system situated within the 7G sector of the Unknown Regions. It housed the ice planet Ilum as its fifth planet, a location of great significance for the instruction of Jedi younglings. Additionally, it included an airless planet at the system's outer reaches. A single star, specifically a blue dwarf referred to as Asar, characterized the system; it was remarkably luminous for its classification. A cometary cloud was also present, residing at a distance from the central star. Following the First Order's construction of a mobile superweapon inside Ilum, the planet shifted its location to a neighboring system.