'Wolf-Rayet' Star 20 Times As Massive As The Sun Explodes In Supernova

Scientists have confirmed that a star 20 times as big as our own died in a giant supernova, which was caught on camera.

A supernova is an enormous explosion caused when a massive star runs out of fuel, collapses and combusts. These super-bright furnaces are the source of the complex elements in the universe from which we and all life on Earth is made.

The new finding is the first direct evidence that these so-called Wolf-Rayet stars are the source of supernovas.

Usually when Wolf-Rayet stars go supernova, the flash overtakes the stellar wind (from which scientists determine what the star looked like before it exploded). In this case scientists were able to catch the supernova before it overtook the wind.

The star (named 'SN 2013cu') was picked out using a new technique for observing the sky known as the intermediate Palomar Transient Factory (iPTF). Using the new sky survey, scientists were catch the star 360 million light years from Earth just hours after it exploded - and watch the event from different telescopes over the next 14 hours.

This real-time data is a "smoking gun" that the star died in a Type IIb supernova, according to Peter Nugent, who heads Berkeley Lab's Computational Cosmology Center.

"When I identified the first example of a Type IIb supernova in 1987, I dreamed that someday we would have direct evidence of what kind of star exploded. It's refreshing that we can now say that Wolf-Rayet stars are responsible, at least in some cases."

"When a Wolf-Rayet star goes supernova, the explosion typically overtakes the stellar wind and all information about the progenitor star is gone. We got lucky with SN 2013cu—we caught the supernova before it overtook the wind. Shortly after the star exploded, it let out an ultraviolet flash from the shock wave that heated and lit up the wind. The conditions that we observed in this moment were very similar to what was there before the supernova."