Archive for November 2007

Hypervelocity Star

One of the fastest moving stars ever seen is challenging theories to explain its blistering speed.

The cosmic cannonball, a neutron star known as RX J0822-4300, was discovered with NASA’s Chandra X-ray Observatory.

Astronomers used five years of Chandra observations to show that the rogue star is careening away from the Puppis A supernova remnant, leftovers of a star that exploded about 3,700 years ago. The neutron star is racing out of our Milky Way Galaxy at about 3 million mph (4.8 million kph).

“Just after it was born, this neutron star got a one-way ticket out of the galaxy,” said co-author Robert Petre, an astronomer at NASA’s Goddard Space Flight Center in Greenbelt, Md. “Astronomers have seen other stars being flung out of the Milky Way, but few as fast as this.”

Other hypervelocity stars known to be exiting the Milky Way move at speeds about one-third as great—likely shot toward interstellar space by an aggressive, supermassive black hole at our galaxy’s center. – Speeding Star to Escape from Milky Way