Their X-ray technique could lead to an early-warning system for exploding stars.
The final, spectacular explosion of a dying star in a galaxy 90 million light-years away may help usher in a new era in understanding these blasts – among the universe’s most violent events.
Astronomers announced Wednesday that they spotted the star in its death throes seconds after the blast and days before it would usually be detected. Supernovae play a key role in seeding the universe with most of its chemical elements. Scientists hope one day to understand the precise mechanism that causes these huge explosions, guided by the technique that allowed the research team to detect Supernova 2008D so early.
Using an orbiting observatory dubbed SWIFT, the team spotted SN 2008D through the explosion’s fledgling X-ray signature. The finding confirms for the first time a longstanding hypothesis that X-rays would be the first radiation this type of supernova would emit – appearing before visible light. (Both forms of radiation took some 90 million years to reach Earth.)
In this case, scientists were able to see the supernova a scant nine seconds after the blast’s shock wave punched through the star’s surface.
The X-ray data contain important clues as to the kind of star that blew up – in this case, an object known as a Wolf-Rayet star, roughly the size of the sun but with 30 times more mass. It lies in a galaxy designated NGC 2770, which appears in the Northern Hemisphere constellation Lynx. Its discovery could lead to a supernova early-warning system that some astronomers say could help revolutionize the study of these events.