Formation of a Fast-Rotating Star
This diagram shows one theory for the creation of the fastest spinning star found to date. The more massive star was once a member of a binary pair. Its rapidly aging companion star evolves and expands, spilling material onto the less evolved star. The star robbed angular momentum from the donor star and spun up to a rotation speed of 1 million miles per hour. The donor star explodes as a supernova and propelled the surviving star away.