The Star is 13.6 Billion Years Old
Australian astronomers have identified the oldest known star in the universe. At an estimated 13.6 billion years old, it was formed just 200 million years after the Big Bang itself. Named SMSS J031300.36-670839.3, it is several hundred million years older than the oldest previously known stars, discovered in 2007 and 2013.
By analyzing light from the star to determine its chemical makeup, the astronomers were able to extrapolate its estimated age. According to members of the astronomy team, an absence of detectable levels of iron in its light spectrum helped determine its age, a distinct “chemical fingerprint” that has never been seen before.
The star was spotted on January 2, 2014, by astronomers at Australian National University (ANU) using ANU’s Skymapper telescope at the Siding Spring Observatory. The telescope is being used in a five-year project to create the first comprehensive digital map of the sky of the Southern Hemisphere. In the first year of this project, Skymapper has photographed over 60 million stars.
Skymapper’s unique capabilities allowed the team to spot the star, located 6,000 light years from Earth in the Milky Way—relatively close in astronomical terms—and analyze its color to determine its lack of iron. The discovery marks the first time that astronomers have been able to study the chemistry of the universe’s first stars. This, in turn, helps scientists create a clearer vision of what the Universe was like in the cosmically-short time following the Big Bang.
The discovery of star SMSS J031300.36-670839.3 was later confirmed using the Magellan telescope in Chile.
For more information, see the latest edition of Nature.