Astronomers Spy Spectacular Supernova and Discover How Stars Explode

Astronomers are learning a bit more about what caused a spectacular supernova in a galaxy about 11 million light-years away. The giant star explosion sheds a bit more light on how galaxies evolved.

The supernova, which is known as 2014J, was first detected with vast networks of radio telescopes. Surprisingly, researchers found from the extremely deep images that there was a lack of radio emissions from the supernova.

The supernova itself was a Type Ia supernova, which is caused by the explosion of a white dwarf star. Once a white dwarf runs out of nuclear fuel, it expands and its core temperature reaches the point where carbon starts to undergo nuclear fusion. This spreads rapidly throughout the star and causes an explosion which rips the star apart as it ejects its outer layers.

"Supernovae play a fundamental role in the chemistry of galaxies and their evolution, as they are responsible for ejecting most of the heavy elements we see around us, including elements that cannot be formed in the interior of normal stars," said Miguel Perez-Torres, one of the researchers, in a news release. "A Nobel Prize was awarded in 2011 for the use of Type Ia supernovae to discover that the expansion of the universe is accelerating. Yet, the basic question of what causes a Type Ia supernova was still a mystery."

In this case, the researchers found that the models of what would have happened to 2014J show that the merger of two white dwarf stars is the most likely cause for the supernova.

"The explosion of a Type Ia supernova is a rare event in the nearby universe," said Rob Beswick, co-author of the new paper. "Supernova 2014J is the closest Type Ia supernova to Earth since 1986, and it's likely that more than a hundred years will pass until we see another such supernova so close to us. This was an amazing opportunity to learn more about these extremely important astrophysical phenomena and their underlying cause."

The findings are published in The Astrophysical Journal.