First Measurement of Uranium/Thorium ratio in a very old Star: Implications for the age of the Galaxy

R. Cayrel

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First Measurement of Uranium/Thorium ratio in a very old Star: Implications for the age of the Galaxy

R. Cayrel

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Abstract

During an ESO-VLT large program devoted to high-resolution spectroscopy of extremely metal-poor stars selected from the H&K survey of Beers and colleagues, a [Fe/H] giant star was found to be as enriched in neutron-capture r-process elements as CS 22892-052, but with a much reduced masking by molecular lines. This allowed the detection and the measurement of the uranium line at 3859 A, for the first time in an extremely old star. Making use of the short 238U decay time (4.47 Gyr) we obtained a radioactive dating of the formation of U and Th in of this star, born in the early days of the Galaxy.

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R. Cayrel. 2001-06-12. First Measurement of Uranium/Thorium ratio in a very old Star: Implications for the age of the Galaxy. https://arxiv.org/abs/astro-ph/0104448

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