GS391

GS391 is a planet, marginally classified as a class M world, with a size slightly smaller than that of Earth. GS391 was a temporary designation assigned by Vulcan scientists T'Clar and Spens when they identified the world as being a possible destination of the lost Vulcan starship He-shii, which disappeared without a trace at some point centuries before the 23rd century.

The USS Enterprise (NCC-1701) arrived at GS391 investigating such a scenario, around the year 2253. The Enterprise found traces of metal from the planet Vulcan on GS391's surface, and a landing party led by Lieutenant Spock discovered a recording from the He-shii indicating that the ship had broken up at GS391 after launching an escape pod bound for Areta.