Galactic fossil dated
Scientists used the VLT to study the star
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Friday, 11, May 2007 11:58
Scientists claim to have dated the age of a star at the edge of our galaxy back to the dawn of time.
Using Eso's very large telescope (VLT) in Chile, astronomers measured the star's age as being 13.2 billion years old - not far off the 13.7 billion year age of our universe.
The research team argues that the star, named HE 1523-0901, therefore formed very early in the life of our galaxy, which must also have formed very soon after the Big Bang.
"Surprisingly, it is very hard to pin down the age of a star," Anna Frebel, lead author of the paper reporting the results, said.
"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."
Age dating of these elements took place along with dating of three other elements: europium, osmium, and iridium.
"Until now, it has not been possible to measure more than a single cosmic clock for a star. Now, however, we have managed to make six measurements in this one star," Dr Frebel added.
The study is published in the Astrophysical Journal.