Polaris — Jack McDevitt

Sixty years ago, the space yacht Polaris was found deserted, the fate of its pilot and passengers a mystery. Now, to mark the anniversary of the disappearance, there is to be an auction of what was left behind on the ship. Using his insider knowledge, Alex Benedict, one of the preeminent antiquities dealers in the Galaxy, secures some of the artifacts. But then an explosion destroys most of the collection, convincing Alex that drastic measures are being taken to hide what happened aboard the Polaris. Which is why that's exactly what he has to find out--especially if it means risking his life...