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Titolo:
Measurement of stellar age from uranium decay
Autore:
Cayrel, R; Hill, V; Beers, TC; Barbuy, B; Spite, M; Spite, F; Plez, B; Andersen, J; Bonifacio, P; Francois, P; Molaro, P; Nordstrom, B; Primas, F;
Indirizzi:
Observ Paris Meudon, DASGAL, F-75014 Paris, France Observ Paris Meudon Paris France F-75014 , DASGAL, F-75014 Paris, France European So Observ, D-85748 Garching, Germany European So Observ Garching Germany D-85748 v, D-85748 Garching, Germany Michigan State Univ, E Lansing, MI 48824 USA Michigan State Univ E Lansing MI USA 48824 Univ, E Lansing, MI 48824 USA Univ Sao Paulo, BR-01060970 Sao Paulo, Brazil Univ Sao Paulo Sao Paulo Brazil BR-01060970 BC01060970 Sao Paulo, Brazil Observ Paris Meudon, DASGAL, F-92195 Meudon, France Observ Paris Meudon Meudon France F-92195 DASGAL, F-92195 Meudon, France Univ Montpellier 2, GRAAL, F-34095 Montpellier, France Univ Montpellier 2Montpellier France F-34095 -34095 Montpellier, France Univ Copenhagen, Astron Observ, DK-2100 Copenhagen, Denmark Univ Copenhagen Copenhagen Denmark DK-2100 , DK-2100 Copenhagen, Denmark Osservatorio Astron Trieste, I-34131 Trieste, Italy Osservatorio Astron Trieste Trieste Italy I-34131 I-34131 Trieste, Italy European So Observ, Santiago 19, Chile European So Observ Santiago Chile19 opean So Observ, Santiago 19, Chile Univ Lund, Lund Observ, S-22100 Lund, Sweden Univ Lund Lund Sweden S-22100 iv Lund, Lund Observ, S-22100 Lund, Sweden
Titolo Testata:
NATURE
fascicolo: 6821, volume: 409, anno: 2001,
pagine: 691 - 692
SICI:
0028-0836(20010208)409:6821<691:MOSAFU>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
METAL-POOR STARS; ABUNDANCE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Cayrel, R Observ Paris Meudon, DASGAL, F-75014 Paris, France Observ Paris Meudon Paris France F-75014 F-75014 Paris, France
Citazione:
R. Cayrel et al., "Measurement of stellar age from uranium decay", NATURE, 409(6821), 2001, pp. 691-692

Abstract

The ages of the oldest stars in the Galaxy indicate when star formation began, and provide a minimum age for the Universe. Radioactive dating of meteoritic material(1) and stars(2) relies on comparing the present abundance ratios of radioactive and stable nuclear species to the theoretically predicted ratios of their production. The radioisotope Th-232 (half-life 14 Gyr) has been used to date Galactic stars(2-4), but it decays by only a factor of two over the lifetime of the Universe. U-238 (half-life 4.5 Gyr) is in principle a more precise age indicator, but even its strongest spectral line,from singly ionized uranium at a wavelength of 385.957 nm, has previously not been detected in stars(4-7). Here we report a measurement of this line in the very metal-poor star CS31082-001(8), a star which is strongly overabundant in its heavy elements. The derived uranium abundance, log(U/H) = -13.7 +/- 0.14 +/- 0.12 yields an age of 12.5 +/- 3 Gyr, though this is still model dependent. The observation of this cosmochronometer gives the most direct age determination of the Galaxy. Also, with improved theoretical and laboratory data, it will provide a highly precise lower limit to the age of the Universe.

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Documento generato il 24/09/20 alle ore 06:18:37