Planet (Castrovalva)

According to the TARDIS Index File, Andromeda was "the planet that form[ed] the Andromedan Phylox Series". Its "central habitation" was Castrovalva. Nyssa told the newly-regenerated Fifth Doctor that was "a small planet".

Unlike its main city, Andromeda was real. When Castrovalva, a block transfer creation of The Master, ceased to exist, Andromeda persisted.

It was, however, unclear whether "Andromeda" was the actual name of that planet. Because the Master admitted that he had instructed Adric to insert false records into the Index File, it was probable that none of the information about Andromeda was true. As far as Nyssa and Tegan were ever able to establish, though, the planet to which they took the Fifth Doctor was called "Andromeda".

Little was known about the planet other than that it had running water and dense foliage. It resembled forests seen on Earth and Tara. (TV: Castrovalva)