Tiaanamat

Tiaanamat was a large inhabited asteroid, orbiting the planet Akhaten in its rings. The asteroid had a molten magma ore.

Tiaanamat played host to the Festival of Offerings, a millennial choral ceremony held when the planet's rings aligned.

The Eleventh Doctor and Clara Oswald visited the vast, winding markets of Tiaanamat, as he had done previously in his first incarnation with his granddaughter. (TV: The Rings of Akhaten)

Behind the scenes
The asteroid is not named in the series itself. The name "Tiaanamat" comes from the BBC Website.