Rogue planet

A rogue planet was a planet which wandered through space instead of orbiting a star.

Mondas became a rogue planet when it left the vicinity of the star Sol; however, following an indeterminate amount of time it returned to the area of space it had left, where it was destroyed. (TV: The Tenth Planet, AUDIO: Spare Parts)

Skardal was a rogue planet which threatened to collide with both Skaro and Mechanus. It was later destroyed by the Dalek. (COMIC: The Rogue Planet, Impasse)

Voga became a rogue planet when most of it was destroyed by the Cybermen. It eventually settled into an orbit around Jupiter. (TV: Revenge of the Cybermen)

Vortis became a rogue planet when the Zarbi Supremo set it on a course to the solar system. (PROSE: The Lair of Zarbi Supremo)