Gamma Arigulon system

From Memory Alpha, the free Star Trek reference

The Gamma Arigulon system is a star system located near the border between the Federation and the Klingon Empire. In 2367, the USS LaSalle reported radiation anomalies within the system and the USS Enterprise-D was dispatched to investigate. The Enterprise initially detected no irregularities from the system's main star. As the starship prepared to launch a Class-1 probe to further investigate the report, a Klingon Vor'cha-class attack cruiser carrying Ambassador K'Ehleyr decloaked on an urgent mission, canceling further investigation of the radiation anomalies. (TNG: "Reunion")