Astronomers go supernova over dying star

23 January 2014

The sudden explosion of a star in a neighbouring galaxy only 11.4 million light years from Earth could give astronomers new clues about the future of the universe.

The Type Ia supernova has lit up the nearby Messier 82 galaxy, and was discovered by amateur astronomers in the past week.

"If you had a wish list of everything could get from a supernova to learn about the universe, this has got it," says ANU astronomer Dr Brad Tucker, who is leading follow-up observations from the ANU Research School of Astronomy & Astrophysics.

The latest discovery is as bright as 10 billion billion lightning bolts and is the closest supernova of its type discovered this close to earth in 150 years.

A supernova is the spectacular end of a star when it blows up.

Dr Tucker said every major telescope in the world was now pointing to the dying star, which could help astronomers better understand dark energy and the fate of the universe. "We have imaged this galaxy lots of times so this is a unique opportunity to see what sort of star it was before it blew up, which gives us information on how it exploded, its mass, energy and brightness," Dr Tucker said.

Messier 82 is a starburst galaxy producing lots of young stars, which in turn produces lots of stellar dust which can affect an astronomer's measurements of distance.

"Because we know a lot about the dust and properties of this galaxy, if we can find the progenitor star, we can calibrate and improve our measurements on all the other supernovae we have data for," Dr Tucker said.

"We can also improve our measurements of dark energy which determines how fast the universe is accelerating, and ultimately its fate."

Dr Tucker said the discovery came from amateur astronomers, who were the first to notice the one-in-a-million event.

"We have data from our telescopes but it's too bright, so it saturated the images," he said.

"It's because of some amateur astronomers that we took a second look."

Amateur astronomers first announced the new piece of light from one of our closest galaxies. Their discovery was backed up by a Japanese space enthusiast taking part in the iTelescope program, where amateur astronomers rent time on remote telescopes, including those at the ANU Siding Spring Observatory.

"Professionals then had a look and did a confirmation where we learned it was a Type Ia supernova and how big it is," Dr Tucker said.

But amateur astronomers in Australia shouldn't reach for their telescopes just yet.

"If you're in the northern hemisphere you can see it with binoculars between the Big and Little Dipper. Unfortunately we can't see this in Australia."