Usually when stars are moved to velocities fast enough to eject a them from the galaxy, the supermassive black hole at the centre is responsible, thanks to the slingshot action of its vast gravity.
But in a new study, scientists have traced the trajectory of a compact helium star, US 708, and deduced that it acted as the mass donor in a type 1a supernova pair, which spun US708 to the point of ejection.