Aya a principal world of the angara.
After the Pathfinder team managed to shut down the machinery in the Eos' vault, a star map was displayed and provided the coordinates to another facility, the planet Aya.
When the Pathfinder team arrived in-system onboard the Tempest, they find themselves pinned between a sizeable kett blockade fleet and a Scourge cloud. Fortunately, SAM managed to calculate a narrow course through The Scourge onto the other side, and successfully shaked the kett fleet as the route is too large for ships above Tempest size, and too dangerous for non-AI pilot to navigate through.
It is due to such natural/un-natural obstacles presented by The Scourge that the angara consider Aya a hidden world, a safe haven from the kett.