NC State astronomer, team solve supernova mystery

Posted October 24, 2011 3:01 p.m. EDT
Updated October 25, 2011 12:16 p.m. EDT

— A team led by an astronomer at North Carolina State University used four space telescopes to figure out why the first documented supernova was super-sized.

State's Brian J. Williams is the lead author of a study published online in the Astrophysical Journal that shows how the star evolved. The star — similar to the sun — died peacefully and turned into a dense white dwarf. It sucked up material from another star, and then exploded in a supernova.

The Chinese first documented the supernova as a "guest star" in their sky in the year 185 over the course of eight months. In the 1960s, scientists identified it as a bigger-than-expected supernova remnant, 8,000 light years away. Each light year is about 6 trillion miles.

Williams' team found that the explosion of the star took place in a cavity in space, allowing stellar shrapnel to travel unimpeded by space dusts and gases and shoot faster and farther out into the universe.

"This supernova remnant got really big, really fast," Williams said. "It's two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we've been able to finally pinpoint the cause."

NASA announced the findings Monday.