Ilum

Ilum is a snow-covered planet located in the 7G sector of the Unknown Regions, within the Ilum system. Ilum is the fifth planet from its parent star Asar, a blue dwarf, located roughly equidistant from Asar and the system's cometary cloud. Ilum had a kyber crystalline core, and had been utilized by the Jedi Order for the Gathering, a rite of passage in which Jedi younglings had to find and harvest kyber crystals for their lightsabers, which had existed for thousands of standard years.

When the Jedi Order was exterminated by order of Darth Sidious, the new Galactic Empire occupied Ilum and began excavating it for its vast supply of kyber crystals, which were to be used in the construction of the first and second Death Stars. The over-mining of the planet caused its core, and later a massive Imperial Trench, to open up along Ilum's equator.