Tiaanamat

Tiaanamat (PROSE: Susan's Diary) was a large inhabited asteroid in the rings orbiting the planet Akhaten.

Tiaanamat played host to the Festival of Offerings, a millennial choral ceremony held when the planet's rings aligned. (TV: The Rings of Akhaten)

Susan bought the Five Hundred Year Diary at Tiaanamat as a present for her grandfather. (PROSE: Susan's Diary)

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 was not named in the The Rings of Akhaten; the name "Tiaanamat" came from production artwork on the BBC website, which explained the asteroids in the Rings of Akhaten as composed of solidifed molten magma ore fragments, with Tiaanamat built as a docking point on the largest piece of ore on the outer ring. The name was later used in-universe in Susan's Diary.