"Spider Star"

Recently from Tor Books: Spider Star by Mike Brotherton.

About the book, from the publisher:

The human colony on the planet Argo has long explored and exploited the technology left behind by an alien race, a race gone for hundreds of thousands of years. But then an archeology team accidentally activates a terrible weapon: a weapon that will destroy the entire colony, and its star, if they cannot deactivate it.

Evidence at the site suggests that the weapon was created for the ancient Argonauts by another race, a race of traders. And within that evidence are a map of their interstellar trading empire, and the coordinates of their main trading station. Although the information is a hundred thousand years out of date, the only hope for Argo is to send a ship and crew into the unknown, to try to negotiate for a way to shut down the weapon.

Visit Mike Brotherton's website.