The
discovery has allowed astronomers for the first time to study the
chemistry of the first stars, giving scientists a clearer idea of what
the Universe was like in its infancy.
"This is the first time
that we've been able to unambiguously say that we've found the chemical
fingerprint of a first star," said lead researcher, Dr Stefan Keller of
the ANU Research School of Astronomy and Astrophysics.
"This is
one of the first steps in understanding what those first stars were
like. What this star has enabled us to do is record the fingerprint of
those first stars."
The star was discovered using the ANU
SkyMapper telescope at the Siding Spring Observatory, which is searching
for ancient stars as it conducts a five-year project to produce the
first digital map the southern sky.
The ancient star is around
6,000 light years from Earth, which Dr Keller says is relatively close
in astronomical terms. It is one of the 60 million stars photographed by
SkyMapper in its first year.
"The stars we are finding number
one in a million," says team member Professor Mike Bessell, who worked
with Keller on the research.
"Finding such needles in a haystack
is possible thanks to the ANU SkyMapper telescope that is unique in its
ability to find stars with low iron from their colour."
Dr Keller and Professor Bessell confirmed the discovery using the Magellan telescope in Chile.
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.
"To
make a star like our Sun, you take the basic ingredients of hydrogen
and helium from the Big Bang and add an enormous amount of iron -- the
equivalent of about 1,000 times the Earth's mass," Dr Keller says.
"To
make this ancient star, you need no more than an Australia-sized
asteroid of iron and lots of carbon. It's a very different recipe that
tells us a lot about the nature of the first stars and how they died."
Dr
Keller says it was previously thought that primordial stars died in
extremely violent explosions which polluted huge volumes of space with
iron. But the ancient star shows signs of pollution with lighter
elements such as carbon and magnesium, and no sign of pollution with
iron.
"This indicates the primordial star's supernova explosion
was of surprisingly low energy. Although sufficient to disintegrate the
primordial star, almost all of the heavy elements such as iron, were
consumed by a black hole that formed at the heart of the explosion," he
says.
The result may resolve a long-standing discrepancy between observations and predictions of the Big Bang.
The discovery was published in the latest edition of the journal Nature.
Story Source:
The above story is based on materials provided by The Australian National University. Note: Materials may be edited for content and length.
http://www.sciencedaily.com/releases/2014/02/140209200836.htm
The above story is based on materials provided by The Australian National University. Note: Materials may be edited for content and length.
http://www.sciencedaily.com/releases/2014/02/140209200836.htm
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