'Cannibal' star eats young star

NASA’s Chandra X-ray Observatory has found evidence of stellar cannibalism. The evidence shows that a 'cannibal' star has recently engulfed a companion star.

india Updated: Sep 16, 2010 13:24 IST

NASA’s Chandra X-ray Observatory Evidence has found evidence that a star has recently engulfed a companion star or a giant planet.

The likely existence of such a “cannibal” star provides new insight into how stars and the planets around them may interact as they age.

The star in question, known as BP Piscium (BP Psc), appears to be a more evolved version of our Sun, but with a dusty and gaseous disk surrounding it. A pair of jets several light-years long blasting out of the system in opposite directions has also been seen in optical data.

While the disk and jets are characteristics of a very young star, several clues -- including the new results from Chandra -- suggest that BP Psc is not what it originally appeared to be.

Instead, astronomers have suggested that BP Psc is an old star in its so-called red giant phase. And, rather than being hallmarks of its youth, the disk and jets are, in fact, remnants of a recent and catastrophic interaction whereby a nearby star or giant planet was consumed by BP Psc.

When stars like the Sun begin to run out of nuclear fuel, they expand and shed their outer layers. Our Sun, for example, is expected to swell so that it nearly reaches or possibly engulfs Earth, as it becomes a red giant star.

“It appears that BP Psc represents a star-eat-star Universe, or maybe a star-eat-planet one,” said Joel Kastner of the Rochester Institute of Technology, who led the Chandra study. “Either way, it just shows it’s not always friendly out there.”

These results appeared in The Astrophysical Journal Letters.

First Published: Sep 16, 2010 12:56 IST