AR Scorpii, previously identified as a single, variable star, is actually two, a compact white dwarf the size of the Earth but 200,000 times more massive, and a cool red dwarf a third the size of the Sun. By examining the system with the Very Large Telescope at the European Southern Observatory, the Hubble Space Telescope and others, astronomers have now learned that the white dwarf is spinning incredibly fast, charging up electrons to almost the speed of light.
via The Terrifying Reason This Star Flickers Every Two Minutes.