Tollan (planet)
From The Stargate Omnipedia
The original homeworld of the Tollan. After the destruction of Serita, a neighboring inhabited planet, Tollan's orbital shift rendered it uninhabitable.
Consequently, the Tollan people were forced to evacuate to a new homeworld, Tollana, while their homeworld suffered massive volcanic destruction.
DETAILS
HOME TO - Uninhabited
FIRST APPEARED - Enigma
KEY EPISODE
Enigma - SG-1 gates to a planet where they uncover the bodies of several advanced humans, and rescue them before their world is destroyed.