S'Arl

From TARDIS Index File, the free Doctor Who reference.

S'Arl was the home planet of the Tzun. It was devastated by the Veltrochni during their wars with the Tzun Confederacy. Using their quantum lances, they were able to cut right through the crust of S'Arl and into the mantle. (MA: The Dark Path)

It is suggested, but not stated, that S'Arl was destroyed in this assault.