NASA Chandra X-ray Observatory finds star moving at hypervelocity speed

William Atkins
Wednesday, 05 December 2007 19:14

Science - Space

The star is called RX J0822-4300. It is a neutron star created from the Puppis A supernova explosion—and it is moving away from the explosion, according to two U.S. scientists, at about three million miles per hour.        

A speed of over three million miles per hour is about 0.5% the speed of light in a vacuum, which is about 186,000 miles per second, or about 300 million meters per second (1.08 billion kilometers per hour).

Puppis A is now called a supernova remnant. It is about ten light-years in diameter. The explosion that caused Puppis A occurred about 3,700 years ago.

Referred commonly as a “Cosmic Cannonball,” RX J0822-4300 is estimated by astronomers to be on a course to take it out of the Milky Way galaxy in millions of years. It is a neutron star, or a star formed from the collapsed remnant of a massive star. Neutron stars are thought to contain mostly neutrons.

U.S. astrophysicist Robert Petre, of the NASA Goddard Space Flight Center (Greenbelt, Maryland), and U.S. physicist Frank Winkler, of the Department of Physics, Middlebury College (Vermont), were the two astronomers who used the Chandra X-ray Observatory over a five-year period to observe this extremely fast moving star. They say that astronomers have found over stars moving millions of miles per hour.

These stars, commonly called “hypervelocity stars,” are thought to gain their speeds from gravitational interactions with huge black holes. One such black hole at the center of the Milky Way galaxy is thought to have ejected stars on a course out of the galaxy at such fast speeds. However, RX J0822-4300 got its speed in a different way. It was ejected by the explosion of a supernova.