Delphi Ardu IV was a planet located somewhere in the space of the galaxy's Alpha or Beta Quadrants, the fourth planet in orbit of the Delphi Ardu star system. The USS Enterprise-D chased a Ferengi warship to Delphi Ardu IV. The planet was the site of an ancient Tkon Empire outpost still protected by a mysterious guardian. (TNG episode: "The Last Outpost")