Atrias

Atrius is a planet formerly inhabited by the xel'naga.

It has a limited amount of vespene gas.

History
The xel'naga constructed a temple on the planet. Dark Prelate Zeratul came to Atrius shortly before the war against Amon. He waited for vespene eruptions to collect enough gas to build up his forces, then confronted the Tal'darim defending the temple.