XI Boötis A system
From Halopedia, the Halo wiki
XI Boötis A was a UNSC colonies star system, located 21.8 lightyears from Sol. It was invaded on October 21, 2528 by the Covenant. Admiral Cole's fleet responded, defeating the Covenant fleet, but taking heavy casualties in the battle. The colony's fate, whether it was glassed or not, and the state of any survivors, is unknown.