A pulsating neutron star believed to have formed 15,000 years ago may be moving at 5.35 million mph, making it the fastest known star in the galaxy, astronomers said.

"This guy is shooting off at 60 times the speed of Earth going around the sun," said Shrinivas R. Kulkarni, associate professor of astronomy at the California Institute of Technology at Pasadena."We haven't conclusively proven this is the case yet, but I'll be very surprised if we're wrong," he said Wednesday in a telephone interview.

Kulkarni, along with Dale Frail, a fellow with the National Radio Astronomy Observatory, observed the pulsar at the Very Large Array radio telescope in central New Mexico.

Researchers may need about three more years to verify the speed, but "I'm willing to take bets on it," Kulkarni said.

Adam Burrows, an associate professor of physics and astronomy at the University of Arizona, said that if the findings are true, "it would force the re-evaluation of some aspects of the form of neutron stars and perhaps supernovae."

"People have got to see this thing and make independent estimates," he said in a telephone interview from Tucson.

The pulsar was born when a massive star collapsed and exploded, ejecting its outer layers that have been sweeping up surrounding interstellar material.

The supernova remnant, dubbed G 5.4-1.2, has been known since the late 1970s. Kulkarni said he and Frail made their observations last August.

Left at the center of the supernova was a star about 6 miles across made entirely of neutrons - dense particles found in the nucleus of atoms.

The neutron star, or pulsar, spins about eight times a second. It's density would be similar to the Earth packed into a cube 700 feet on each side.

When the massive star transformed into a supernova, the remaining pulsar kicked off in one direction.