Star Wars Episode 0: The Requel
Yavin is a gas giant orbited by 26 moons, some of which are habitable. The gas giant itself has no significant gas mining activity, as it is plagued by storms that would tear apart most ships. Yavin 4, Yavin 8 and Yavin 13 are the habitable moons.
Yavin 4 has been a place of historical significance, and has been inhabited for thousands of years, including events in the long history of the Jedi and the Sith sect. It is geologically active and covered in flora that store massive amounts of moisture, maintaining a high level of humidity. There are places on Yavin 4 that rain almost incessantly, particularly in the shadow of jagged mountain ranges.