Perseant Alpha was a star system, located somewhere in the space of the galaxy's Alpha or Beta Quadrants.
History and specifics[]
In the year 2265, the USS Enterprise traveled through the center of the Perseant Alpha system. It was considered a matter of routine, but several hours later, the ship passed through a temporal disruption that sent it into a different star system 800 years into the past. (TOS comic: "Vibrations in Time")