SYDNEY, Feb 10 (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)
