Lalande 21185 was a star in the constellation of Ursa Major. (PROSE: Return of the Living Dad) The fourth planet orbiting the star was home to the Caxtarids. (PROSE: The Room With No Doors)
Every living thing on the Caxtarid planet was killed by a virus released during a rebellion two Lalandan years after 1983. Evacuations were planned, but even the ships they would have used to escape were chewed up. (PROSE: Return of the Living Dad) When Pyke-Xi Raul heard two Caxtarid slavers mention their homeworld, he reckoned it meant he was between the years 2600 BC and 1975 AD. (PROSE: Wringing Off)
One potential future incarnation of the Doctor was worshipped as a god on Lalande 21185. (PROSE: So Vile a Sin)