The Cordannas system was a star system with a white dwarf primary. It was 12 hours from Tambor Beta-6 at warp 9.

In 2370, a network of emergent circuit nodes, having taken control of the USS Enterprise-D, plotted a course to the Cordannas system after they exhausted the supply of vertion particles at Tambor Beta-6. The Enterprise crew was able to divert the ship to the MacPherson Nebula instead, as their life support system would have failed before they reached Cordannas. (TNG: "Emergence")

This system was only mentioned in dialogue.
According to the script, Cordannas was pronounced as "kore-DAN-us".