Sentera V was a planet, a class F planet located somewhere in the space of the galaxy's Alpha or Beta Quadrants, the sixth planet in orbit of the SK-739 star system.
History and specifics[]
When Data was fleeing Jem'Hadar pursuit in early 2374, during the Dominion War, he landed his shuttlecraft, the Cook, on SK-739-6, on a huge ice sheet of frozen solid chlorine dioxide. (TNG - The Dominion War novel: Tunnel Through the Stars)