Astronomers find fastest rotating star

Posted by Kate Taylor

Astronomers say they've discovered their fastest-spinning star, a hot blue giant rotating at a million miles per hour - 100 times faster than our sun.

If it spun much faster, they say, it would be torn apart by centrifugal force.

The star, called VFTS 102, was discovered using the European Southern Observatory's Very Large Telescope at the Paranal Observatory in Chile. It lies in a neighboring dwarf galaxy, the Large Magellanic Cloud, about 160,000 light-years from Earth.

The astronomers believe that it may have had a violent past and has been ejected from a double star system by its exploding companion, as it's moving through space at a significantly different speed from its neighbors.

"The remarkable rotation speed and the unusual motion compared to the surrounding stars led us to wonder if this star had an unusual early life. It was suspicious," says Philip Dufton of Queen's University Belfast.

If the star could have started life as one component of a close binary star system, gas from the companion could have streamed over and in the process the star would have spun faster and faster.

After about ten million years, the massive companion would have exploded as a supernova, ejecting the super-fast star. As it collapsed, the massive companion would then have turned into a pulsar - and it may be significant that there is indeed a nearby supernova remnant and a pulsar.

"This is a compelling story because it explains each of the unusual features that we've seen," says Dufton. "This star is certainly showing us unexpected sides of the short but dramatic lives of the heaviest stars."

The team hopes to use NASA's Hubble Space Telescope to test the theory.