UH scientist helps study supernova

By Kevin Dayton
Advertiser Big Island Bureau

A University of Hawai'i astronomer is part of a team that probed the mystery of an odd supernova that occurred in 1993, proving the supernova exploded next to a companion star.

Scientists theorize the pull from the companion star ripped the "envelope" off the exterior of a red supergiant star, causing it to burn in an unexpected pattern that included a bizarre increase in brightness, said Rolf-Peter Kudritzki, who worked with a team of European astronomers.

Supernovas occur when stars of more than eight times the size of our sun burn to the end of their energy and collapse under their own weight.

Almost all supernovas explode and fade in a predictable pattern, "but this one didn't," Kudritzki said. The supernova known as SN 1993J, in spiral Galaxy M81, behaved very differently.

"It had a very unusual light curve, it became bright, then it became fainter, and then it became bright again," said Kudritzki, who is director of the UH Institute for Astronomy.

About half of all stars are in "binary" systems made up of two stars orbiting each other, and astronomers theorized the supernova star orbited a companion star, which shredded the outer material on the red supergiant before it exploded, causing the strange light.

Using the W.M. Keck Telescope on Mauna Kea and the Hubble Space Telescope, astronomers looked deep into the 10-year-old supernova remnant and finally located the companion star that remained after the explosion.

Their findings are published today in the journal Nature.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com or (808) 935-3916.