US 708 is Milky Way’s fastest-moving stellar escapee
Ruth Bazinet, CfA
Some stars are in a rush to get out of the galaxy. One such star is hurtling away from the Milky Way at roughly 4.3 million kilometers per hour, researchers report in the March 6 Science, making it the fastest-moving star to be ejected from our galaxy.
The escapee, designated US 708, might have been propelled by a stellar explosion known as a type 1a supernova, suggest Stephan Geier, an astronomer at the European Southern Observatory in Garching, Germany, and colleagues. If their proposal is true, then astronomers could use stars like US 708 to probe the origin of type 1a supernovas, which are among the most powerful explosions in the universe.
US 708 is one of roughly a couple dozen hypervelocity stars, which travel so fast they can flee the galaxy. Researchers suspect that most hypervelocity stars are shot out of the Milky Way after a close brush with the supermassive black hole that