Theyar is a large gas giant with traces of chlorine and sodium in its atmosphere. It also has a significant amount of water vapor in the clouds of its upper atmosphere.
Theyar was struck by an asteroid at least 12 kilometers in diameter within the last hundred years. The superheating caused by the impactor's atmospheric passage created a large bank of vicious storms along the equatorial band.
- The Official Game Guide for Mass Effect doesn't include this planet in the planetary database on page 275.