Strange Neutron Star is Racing Through Milky Way at 3 Million MPH

One of the the fastest-moving stars ever discovered in the Milky Way is challenging theories about why it's moving so fast.

The object is a piece of the Puppis A supernova remnant created when a massive star ended its life in a supernova explosion about 3,700 years ago, forming an incredibly dense object called a neutron star.

Astronomers used five years of NASA's Chandra X-ray Observatory images to show that the rogue star, poetically dubbed RX J0822-4300 (shown in image moving from point A in 1999 to point B in 2005), is careening away from what's left of a star that exploded about 3,700 years ago. The neutron star is exiting the Milky Way at about 3 million mph (4.8 million kph). Other hypervelocity stars known to be exiting the Milky Way move at speeds about one-third as great - believed to be hurled toward interstellar space by an aggressive, supermassive black hole at our galaxy's center.

"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."

In the case of RX J0822-4300, a tremendous lopsided supernova explosion launched the neutron star to its blinding speed. It has traveled 20 light-years thus far, and will take millions of years to escape the clutches of the Milky Way. Despite using advanced computer models to simulate how such a stellar rocket could form, astronomers have no concrete explanation.

Posted by Casey Kazan.

Link:

http://news.xinhuanet.com/english/2007-11/29/content_7167962.htm