Kotati was mentioned as being contacted by USS Voyager in 2372 in its subspace communications logs.

Neelix skimmed over this communication while looking for "something anomalous" in the logs. (VOY: "Investigations")

It was not clear from dialoge if Kotati was a planet, a ship, or something else.
Both and the Star Trek Encyclopedia (4th ed., vol. 1, p. 440) identified it as a Delta Quadrant planet. The Star Trek: Star Charts (p. 84) depicted it as a star system with a F-class star. Voyager contacted this system on stardate 49485.