Alpha Onias III
From Star Trek : Freedom's Wiki
Alpha Onias III is a planet located dangerously close to the Romulan Neutral Zone and the Romulan Star Empire. During the federation civil war it served as the secret headquarters for the Government in Exile and the location of the Exiled UFP President Rondar Nell.
The USS Specter was sent to this planet to meet with some members of the government in Exile to learn the actual location of the Exiled UFP president. The purpose was to have Nell on hand to assume the control of the UFP Government immediately after the Battle of Sector 001.