Solarion IV is the fourth planet in the Solarion system, where a Federation colony was located. In 2368, the colony on Solarion IV was attacked and destroyed by an unidentified vessel. Shortly after, a Bajoran splinter group led by Orta apparently claimed responsibility for the attack, prompting Admiral Kennelly to assign the USS Enterprise-D to investigate the threat. It was eventually found that the Cardassians had attacked the colony to frame Orta, so that Starfleet would draw him into the open. (TNG: "Ensign Ro")