Oldest Star Formed Shortly After the Big Bang Discovered by Australian Astronomers

A team of Australian researchers has located a new star around 6,000 light years away from  Earth formed shortly after the Big Bang.

The team led by astronomers at The Australian National University discovered the ancient star dubbed SMSS J031300.36-670839.3, which according to them was formed 13.7 billion years ago shortly after the Big Bang.  The researchers say this gives them an opportunity to study in detail the chemistry of the early stars. With this information the astronomers will be able to get an idea of the universe 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," lead researcher, Dr Stefan Keller of the ANU 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."

Discovered using ANU SkyMapper telescope at the Siding Spring Observatory, the ancient star is one of the 60 million stars that were photographed by SkyMapper in its first year. The SkyMapper telescope is on a mission to hunt ancient stars and during the five year project it will create the first digital map of the Southern Sky.

The composition reveals that the star was formed after a primordial star, 60 times massive than the sun, met its end after a supernova explosion.

"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."

Till date it was believed that when primordial stars died a violent explosion dumped huge volume of iron in to space. But this star has signs of lighter elements like carbon, magnesium and no iron, clearly indicating that the explosion of supernova was of low energy, adequate enough to split the primordial star but the iron was absorbed by the black hole formed in the centre of the exploding star.

This oldest star breaks the record of HD 140283 also called as the Methuselah star that is 14.5 billion years old. Because, this star has higher oxygen -iron ratio than what was previously thought. As the universe aged, it became rich in oxygen. Hence more oxygen means younger star. Based on the new observations HD 140283 would be about 13.2 billion years old, says IB Times.

This oldest star was found using the Magellan telescope in Chile. The discovery was published in the journal Nature.