Orphan planet
From Tardis Wiki, the free Doctor Who reference
According to the Thirteenth Doctor, orphan planet was a grading that meant that a formerly habitable planet had become too toxic for life and was now uninhabitable. In societies that let this happen, there was often a ruling elite that managed to evacuate, then signed off all responsibility for whatever they had left behind; all sentient life died and the planet was classified as orphan.
In a unknown future after 2020, in a possible timeline, there were at least 54 orphan planets by the time Earth itself became one, being designated as Orphan 55. (TV: Orphan 55)
