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Measurement of stellar age from uranium decay

Cayrel, R.; Hill, V.; Beers, T. C.; Barbuy, B.; Spite, M.; Spite, F.; Plez, B.; Andersen, J.; Bonifacio, P. and François, P., et al. (2001) In Nature 409(6821). p.691-692
Abstract
The ages of the oldest stars in the Galaxy indicate when star formationbegan, and provide a minimum age for the Universe. Radioactive dating ofmeteoritic material and stars relies on comparing the present abundanceratios of radioactive and stable nuclear species to the theoreticallypredicted ratios of their production. The radioisotope <SUP>232</SUP>Th(half-life 14Gyr) has been used to date Galactic stars, but it decays byonly a factor of two over the lifetime of the Universe. <SUP>238</SUP>U(half-life 4.5Gyr) is in principle a more precise age indicator, buteven its strongest spectral line, from singly ionized uranium at awavelength of 385.957nm, has previously not been detected in stars. Herewe report a... (More)
The ages of the oldest stars in the Galaxy indicate when star formationbegan, and provide a minimum age for the Universe. Radioactive dating ofmeteoritic material and stars relies on comparing the present abundanceratios of radioactive and stable nuclear species to the theoreticallypredicted ratios of their production. The radioisotope <SUP>232</SUP>Th(half-life 14Gyr) has been used to date Galactic stars, but it decays byonly a factor of two over the lifetime of the Universe. <SUP>238</SUP>U(half-life 4.5Gyr) is in principle a more precise age indicator, buteven its strongest spectral line, from singly ionized uranium at awavelength of 385.957nm, has previously not been detected in stars. Herewe report a measurement of this line in the very metal-poor starCS31082-001<SUP>8</SUP>, a star which is strongly overabundant in itsheavy elements. The derived uranium abundance, log(U/H) = -13.7 +/- 0.14+/- 0.12 yields an age of 12.5 +/- 3Gyr, though this is still modeldependent. The observation of this cosmochronometer gives the mostdirect age determination of the Galaxy. Also, with improved theoreticaland laboratory data, it will provide a highly precise lower limit to theage of the Universe. (Less)
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Nature
volume
409
issue
6821
pages
691 - 692
publisher
Nature Publishing Group
external identifiers
  • wos:000166816400035
  • scopus:0035825685
ISSN
0028-0836
DOI
10.1038/35055507
language
English
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yes
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76b1545c-3c9a-4f0e-8559-78da23cd6376 (old id 130232)
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2007-07-12 15:38:17
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@article{76b1545c-3c9a-4f0e-8559-78da23cd6376,
  abstract     = {The ages of the oldest stars in the Galaxy indicate when star formationbegan, and provide a minimum age for the Universe. Radioactive dating ofmeteoritic material and stars relies on comparing the present abundanceratios of radioactive and stable nuclear species to the theoreticallypredicted ratios of their production. The radioisotope &lt;SUP&gt;232&lt;/SUP&gt;Th(half-life 14Gyr) has been used to date Galactic stars, but it decays byonly a factor of two over the lifetime of the Universe. &lt;SUP&gt;238&lt;/SUP&gt;U(half-life 4.5Gyr) is in principle a more precise age indicator, buteven its strongest spectral line, from singly ionized uranium at awavelength of 385.957nm, has previously not been detected in stars. Herewe report a measurement of this line in the very metal-poor starCS31082-001&lt;SUP&gt;8&lt;/SUP&gt;, a star which is strongly overabundant in itsheavy elements. The derived uranium abundance, log(U/H) = -13.7 +/- 0.14+/- 0.12 yields an age of 12.5 +/- 3Gyr, though this is still modeldependent. The observation of this cosmochronometer gives the mostdirect age determination of the Galaxy. Also, with improved theoreticaland laboratory data, it will provide a highly precise lower limit to theage of the Universe.},
  author       = {Cayrel, R. and Hill, V. and Beers, T. C. and Barbuy, B. and Spite, M. and Spite, F. and Plez, B. and Andersen, J. and Bonifacio, P. and François, P. and Molaro, P. and Nordström, Birgitta and Primas, F.},
  issn         = {0028-0836},
  language     = {eng},
  number       = {6821},
  pages        = {691--692},
  publisher    = {Nature Publishing Group},
  series       = {Nature},
  title        = {Measurement of stellar age from uranium decay},
  url          = {http://dx.doi.org/10.1038/35055507},
  volume       = {409},
  year         = {2001},
}