Prison planet
From Tardis Wiki, the free Doctor Who reference
A prison planet was a planet used by a species, group or organisation as a prison. Some prison planets resembled prisons, such as the Stormcage Containment Facility and Volag-Noc. (TV: The Pandorica Opens, The Infinite Quest) Another prison planet was Dis, used by the Imperial Landsknechte during the rule of the Earth Empire as a prison due to its proximity to a sun. (PROSE: Original Sin)
Some planets were chosen as prison planets to serve dual roles as a prison environment and sourcing a rare or useful material: New Rarga, where wompom was grown and harvested, and Raaga, a world rich in tinclavic. (PROSE: Ghost Devices, TV: The Visitation)
