El-Aurian system

From Memory Alpha, the free Star Trek reference

The El-Aurian system was the star system located several thousand light years from Federation space, near System J-25. The system contained at least one populated planet, the El-Aurian homeworld.

During the late 23rd century the system was invaded and a majority of its population was assimilated by the Borg. Those El-Aurians who managed to survive the invasion were scattered throughout the galaxy. (TNG: "Q Who"; Star Trek Generations)

Odo identified Martus Mazur as a refugee from the El-Aurian system during Mazur's visit to Deep Space 9 in 2370. (DS9: "Rivals")