Pellion was a star system, located somewhere in the space of the galaxy's Alpha or Beta Quadrants.
History and specifics[]
The Federation starship USS Endeavour was performing a science survey in the Pellion system, in the 2260s decade of the Kelvin timeline. The scientific mission was cut short when the Endeavor received a distress call from the USS Concord. (TOS - Boldly Go comic: "Issue 1")