A large cluster galaxy (centre of the box), which has split light from an exploding supernova in a magnified background galaxy into four yellow images (arrows). Photo: Nasa/PA WireAstronomers 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, researchers said.
The star, known as US 708, is travelling at about 1,200km per second, fast enough to actually leave the Milky Way galaxy in about 25 million years, said astronomer Stephan Geier with Germany-based European Southern Observatory, which operates three telescopes in Chile.
“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 slingshot in a supernova explosion.
The 20 other stars discovered so far that are heading out of the galaxy likely got their impetus from coming too close to the supermassive black hole that lives at the centre of the Milky Way, scientists report in an article in this week’s edition 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.
If confirmed, these types of ejected stars may provide more insight into how supernova explosions occur.
Since the explosions give off a fairly standard amount of radiation, scientists can calculate their distances by measuring how bright or dim they appear and determine how fast the universe is expanding.