Goja V is an asteroid within Betazed's defense system, where Caleb's mother Anisha was held before she escaped.
Goja V is a name that Caleb Mir first hears from Nus Braka, who claims that Caleb's mother Anisha was once held there. In Beta Test, Caleb and Chancellor Ake find no record of any planet by that name.
During the Betazoid delegation's visit, Tarima Sadal reveals to Caleb that Goja V is actually an asteroid within Betazed's defense system. By the end of the episode, Ake tells Caleb that Starfleet Intelligence has confirmed his mother escaped from Goja V.