Ceres

Ceres was a dwarf planet in the Sol system, located in the asteroid belt between Mars and Jupiter. (AUDIO: The Bounty of Ceres)

At some point, Ceres was home to the Cerulians until their civilisation was destroyed by an incoming asteroid. (TV: Sirens of Ceres)

Ceres was later visited by the First Doctor, Vicki and Steven. By this time, the dwarf planet was devoid of any native life forms. A Cobalt Corporation mining base was located there. (AUDIO: The Bounty of Ceres)

Behind the scenes
Although not mentioned, in Resolution it was implied the Thirteenth Doctor and her companions helped its discovery by Giuseppe Piazzi.