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RSAA News of the Month: May 2007

Astronomers find a star from the dawn of time

Using ESO’s VLT during her PhD studies at RSAA, Anna Frebel (now at McDonald Observatory, Texas), and her collaborators including John Norris (RSAA) and Norbert Christlieb (Uppsala University) have analysed one of the oldest stars yet found in the Universe.

The star, HE 1523-0901, is measured to be 13.2 billion years old - not far from the 13.7 billion years age of the Universe.

"Surprisingly, it is very hard to pin down the age of a star", Dr Frebel explains. "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."

The aging technique is much like carbon-14 dating used in archaeology. The difference is that instead of looking at time spans of a few thousand years, vastly longer timescales are involved.

According to Professor Norris: "This is probably one of the first stars ever to form. It was born close to the beginning of time."

For more information, see the ESO Press release

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