Telescopes around the world and in space have been watching the brightest example ever seen of a rare type of exploding star. The cosmic blast, 3.7 billion light-years away, was spotted by a robotic telescope operated by the University of Texas.

Dubbed Supernova 2008am, it became more than 100 billion times brighter than the Sun.

Experts calculate that it emitted more energy in one second than would satisfy the USA’s power needs for a million times longer than the universe has existed!

The exploding star is of a kind identified only a few years ago. Its extreme brightness was caused when a debris thrown off by the star collided with a shell of gas that it had earlier ejected.

This type of supernova is 100 times brighter than normal supernovas and may only explode in a galaxy once every 100,000 years.

Before exploding, it is thought to have been a star called a “luminous blue variable”, a massive star that has a shot life of only a million years.

The record-breaker was discovered in an anonymous galaxy in the constellation of Coma Berenices by astronomers led by graduate student Emmanouil “Manos” Chatzopoulos and Dr J Craig Wheeler of The University of Texas, Austin. It add to a new class of exploding stars that the university’s astronomers identified a few years ago.

The supernova was detected by the ROTSE Supernova Verification Project (previously called the Texas Supernova Search), which uses the 18-inch robotic ROTSE IIIb Telescope at Austin’s McDonald Observatory.

Details of the discovery are published in the latest Astrophysical Journal. You can read the university’s release here.

Despite its brilliance, the supernova was so far away that its blast was only visible in large telescopes. But astronomers believe there is a star much closer to home in our own Milky Way that will explode in a similar way one day.

Called Eta Carinae, it has been seen to fluctuate wildly in brightness after throwing off clouds of debris, occasionally becoming one of the brightest stars in the night sky. It lies “only” 8,000 light-years away from us and is expected to destroy itself within the next 100,000 years.

Another supernova candidate closer to home is Betelgeuse, the bright red star in Orion. Though it lies about 640 light-years from us, we are not in any danger.

• Discover space for yourself and do fun science with a telescope. Here is Skymania’s advice on how to choose a telescope. We also have a guide to the different types of telescope available. Check out our monthly sky guide too!
©PAUL SUTHERLAND, Skymania.com

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