Astronomers have found a star hurtling through the galaxy faster than any other, the result of being blasted away by the explosion of a massive partner star. The star, known as US 708, is traveling at about 746 miles (1,200 kilometers) per second, fast enough to actually leave the Milky Way galaxy in about 25 million years, said Stephan Geier, an astronomer with the European Southern Observatory.
"At that speed you could travel from Earth to the moon in five minutes," noted University of Hawaii astronomer Eugene Magnier.
US 708 is not the first star astronomers have found that is moving fast enough to escape the galaxy, but it is the only one so far that appears to have been powered by a supernova explosion. The 20 other stars probably encountered a slingshot effect after coming too close to the supermassive black hole at the center of the Milky Way, scientists report in this week’s issue of the journal Science.
Before it was sent streaming across the galaxy, US 708 was once a cool giant star, but it was stripped of nearly all of its hydrogen by a closely orbiting partner. Scientists suspect it was this feeding that triggered the partner’s detonation.