sentences:  GCIRS 13E is a small cluster dominated by a few massive stars.It is thought that massive stars cannot form so close to a supermassive black hole and since such massive stars have a short lifespan it is thought that GCIRS 13E must have migrated inward toward the central black hole within the past 10 million years, probably from about 60 light-years further out than its current orbit.The stars are possibly the remains of a globular cluster where a middleweight black hole such as could develop through runaway star collisions.