An F-type star was a classification of star.
Orellius Minor is an F-type star in Sector 401, and primary of the Orellius system. In 2370, Alixus attempted to destroy the USS Rio Grande by sending it into Orellius Minor. However, the trajectory was off and the runabout was later sighted in open space by the Romulan vessel Gasko. (DS9: "Paradise")
Kelis' homeworld was the fourth planet orbiting an F-type star, in the Delta Quadrant. (VOY: "Muse")