Not only is HM Cancri the fastest binary star system every discovered, but it is almost the fastest binary star system possible. If they orbited each other any more quickly, say, on the order of three minutes per orbit, the stars would pull so close that they would begin siphoning helium off one another. At that point, the system would experience a special kind of supernova. The resulting blast would then slow down the system. So it looks like, even in space, speed kills.