PARIS: Astronomers have used a unique process to determine that a star in our galaxy is nearly as old as the universe itself.

The star is 13.2 billion years old, while the universe dates back 13.7 billion years, according to the European Organisation for Astronomical Research in the Southern Hemisphere (ESO).

A group of international astronomers used the ESO’s powerful VLT telescope to measure radioactive elements thorium and uranium to determine the star’s age. The technique is similar to carbon dating methods used in archaeology to measure time spans of up to a few tens of thousands of years, the ESO said.

Astronomers, however, must work with much longer timescales, it said.

“Surprisingly, it is very hard to pin down the age of a star,” Anna Frebel, the lead author of a paper on the results, said in a statement.

“This requires measuring very precisely the abundance of the radioactive elements thorium or uranium, a feat only the largest telescopes such as ESO’s VLT can achieve,” she said.

The organisation said “this star very clearly formed very early in the life of our own galaxy,” which is believed to itself have formed soon after the Big Bang. The star’s name is HE 1523-0901.

The group’s research was published in the May 10 issue of Astrophysical Journal.—AFP