Ancient star helps scientists understand universe's origins

SYDNEY Sun Feb 9, 2014 11:16pm EST

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SYDNEY (Reuters) - Australian astronomers have found the oldest known star in the universe, a discovery that may help to resolve a long-standing discrepancy between observations and predictions of the Big Bang billions of years ago.

Dr Stefan Keller, lead researcher at the Australian National University Research School, told Reuters his team had seen the chemical fingerprint of the "first star". After 11 years of searching, the star was discovered using the SkyMapper telescope at the Siding Spring Observatory.

"This star was formed shortly after the Big Bang 13.7 billion years ago," Keller said.

"It's giving us insight into our fundamental place in the universe. What we're seeing is the origin of where all the material around us that we need to survive came from."

Simply put, the Big Bang was the inception of the universe, he said, with nothing before that event.

The ancient star is about 6,000 light years from Earth - relatively close in astronomical terms. It was one of 60 million stars photographed by SkyMapper in its first year.

"This is the first time we've unambiguously been able to say we've got material from the first generation of stars," Keller said. "We're now going to be able to put that piece of the jigsaw puzzle in its right place."

The composition of the newly discovered star shows it formed in the wake of a primordial star, which had a mass 60 times that of our Sun.

Keller said it was previously thought primordial stars died in extremely violent explosions that polluted huge volumes of space with iron. But the ancient star shows signs of pollution with lighter elements such as carbon and magnesium - with no sign of iron.

"What that means is we had a long-held theory that the first stars to form would be extremely massive because they are formed out of pure hydrogen and helium," he said.

"A star is like an onion - it has all these layers and the heaviest material like iron is right down in the core. The only thing to come out of it was the carbon and a little bit of magnesium from that supernova and that's what we're seeing today in the star that we've discovered."

The discovery was published in the latest edition of the journal Nature.

(Reporting by Pauline Askin; Editing by John O'Callaghan)

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Comments (6)
michael10sley wrote:
I’m a bit confused. I thought the earliest stars formed at the edge of the visible universe, 13 billion years ago, as visualized by the famous Hubble Deep Field program. How can a star which formed that early be only 6000 light years from us ?

Feb 10, 2014 9:37am EST  --  Report as abuse
gregbrew56 wrote:
The stars at the “edge” of the observable universe are the ones that were going the fastest (relative to Sol), so they are the furthest away from us, and the light we see from them is the oldest, having left them ~13 billion years ago. This (relatively) nearby one just wasn’t one of the fast-movers (relative to Sol) during the expansion.

Feb 10, 2014 11:49am EST  --  Report as abuse
LawyerTom1 wrote:
The use of the term “pollution” to describe the process of element formation in a star is, to be polite, scientifically incorrect. The elements are formed in the fusion process and are part of the “evolution” of a star over time. These are not contaminants, but natural byproducts of the fusion process.

Feb 10, 2014 12:02pm EST  --  Report as abuse
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