Australian National University researchers have discovered the oldest known star in the universe. Researchers said that the star, SMSS J031300.36-670839.3, is believed to have formed shortly after the Big Bang, nearly 13.7 billion years ago.
By closely examining the chemistry of the first stars, astronomers can determine the Universe's 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," Lead researcher Dr Stefan Keller of the Research School of Astronomy and Astrophysics said in a statement. "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 ancient star, around 6,000 light years from Earth, was discovered using the ANU SkyMapper telescope at the Siding Spring Observatory. The researchers confirmed the discovery using the Magellan telescope in Chile.
"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 said. "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."
According to the Massachusetts Institute of Technology, the Big Bang created hydrogen and helium that subsequently collapsed to form the first stars. These massive, luminous, short-lived objects exploded as supernovae soon after, giving rise to a second generation of stars. Dr.Keller said that the scientists previously thought that the supernovae were extremely violent explosions which spewed the space with the first heavy elements in huge volumes such as carbon, iron, and oxygen.
The ancient star discovered by the Australian astronomers showed evidence of pollution with lighter elements such as carbon and magnesium and was found to contain less iron than previously believed.
"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," Keller said.
The finding is published in the journal Nature.
