Supernova Discovery Reveals Demise of Space's Biggest, Brightest Stars

Scientists recently discovered a supernova that provided them with the most direct evidence that space's biggest and brightest stars explode when they die.

These stars are Wolf-Rayet stars, which are more than 20 times as massive as the sun and at least five times as hot, Space.com reported. Only a few hundred are known to be in existence.

The intense heat of Wolf-Rayet stars forces their own matter apart, making them not only hot but also extraordinarily windy. With up to 5.6 million mph winds, they usually lose mass equivalent to that of the Earth each year.

Astronomers have long believed that these titans violently destructed as supernovas, but the gigantic amounts of matter they exude prevents further study.

"Finding what kind of star exploded, after it already exploded, is, of course, a hard problem, since the explosion destroys much of the information," said study author Avishay Gal-Yam, an astrophysicist at the Weizmann Institute of Science in Israel.

But this is changing, thanks to an innovative sky survey called the intermediate Palomar Transient Factory (iPTF), which exposes fleeting cosmic events such as supernovae, according to Phys.org.

For the first time ever scientists have confirmed that a Wolf-Rayet star - located 360 million light-years away in the Bootes constellation - died in a supernova.

The explosion is known as a Type IIb supernova, meaning it took place after the core of its star ran out of fuel, collapsing into an extremely dense nugget in a fraction of a second and rebounding with a blast outward.

What is left after a supernova is either a black hole or a neutron star, according to Space.com.

Using iPTF's resources, astronomers were able to catch supernova SN 2013cu within hours of its explosion. They then triggered ground- and space-based telescopes to observe the event approximately 5.7 hours and 15 hours after it self-destructed.

"Newly developed observational capabilities now enable us to study exploding stars in ways we could only dream of before. We are moving towards real-time studies of supernovae," Gal-Yam said.

The explosion gives the star's surrounding molecules electrical charges that then emit light. This "tells us the elemental composition of the wind, and hence the surface composition of the star as it was just before it exploded," Gal-Yam added, although this opportunity lasts just for a day before the evidence is swept away.

"This is the smoking gun. For the first time, we can directly point to an observation and say that this type of Wolf-Rayet star leads to this kind of Type IIb supernova," commented Peter Nugent, who was involved in the study.

They detail their findings in the May 22 issue of the journal Nature.