Selek IV was the inhabited fourth planet in its star system in the Delta Quadrant.

In 2377, Gar was en route to a gambling tournament on Selek IV when he was apprehended by the USS Voyager for stealing the EMH. (VOY: "Critical Care")

This planet was only mentioned in dialogue.
According to Star Trek: Star Charts (p. 94), the primary of the Selek system was a M-class star.