Newfound Monster Supernova Breaks Records

A small portion of one of the fields from the Supernova Legacy Survey showing SNLS-06D4eu and its host galaxy (arrow). Superbright points of light with spikes are stars in the foreground. Credit: UCSB

A newly discovered exploding star may have broken two cosmic records, as it’s both the brightest and the most distant supernova ever seen, according to a new study.

Located about 10 billion light-years from Earth, the supernova dubbed SNLS-06D4eu is hundreds of times brighter than the typical supernova. This has led the astronomers with the Supernova Legacy Survey (SNLS), who made the find, to believe they may have stumbled across a whole new species of these dying massive stars, which they are calling “superluminous supernovae.”

First spotted as a faint ultraviolet speck on images six years ago, researchers initially were not sure what they had found. Its extreme brightness could not be explained by current theories of what powers supernovae. A supernova is generally thought to occur when nuclear fuel runs out in the star’s core, which causes it to suddenly collapse into a neutron star or black hole.

“At first, we had no idea what these things were, even whether they were supernovae or whether they were in our galaxy or a distant one,” said lead author D. Andrew Howell, an astronomer at the University of California, Santa Barbara, in a statement.

“I showed the observations at a conference, and everyone was baffled. Nobody guessed they were distant supernovae because it would have made the energies mind-bogglingly large. We thought it was impossible.”

Researchers eventually came up with a new model that perfectly fits their observations and explains the internal mechanisms at work in this new class of cosmic beasts. The new models suggest that highly magnetized, fast-spinning neutron stars (called magnetars) might be the key progenitors of superluminous supernovae that provide the energy necessary to create such powerful explosions.

“What may have made this star special was an extremely rapid rotation,” said co-author Daniel Kasen of the University of California, Berkeley.

“When it ultimately died, the collapsing core could have spun up a magnetar like a giant top. That enormous spin energy would then be unleashed in a magnetic fury.”

The universe was just shy of four billion years old when the superluminous supernova burst. Howell and his team believe that it may be a remnant of a bygone time when mature galaxies, like our own Milky Way, were still just forming.

“These are the dinosaurs of supernovae,” said Howell.

“They are all but extinct today, but they were more common in the early universe. Luckily we can use our telescopes to look back in time and study their fossil light. We hope to find many more of these kinds of supernovae with ongoing and future surveys.”

The record supernova finding appears in the Dec. 20 issue of the Astrophysical Journal.

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Changing Planet

Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.