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Li in carbon-enhanced metal-poor stars

par Masseron, Thomas ;Johnson, Jennifer J.A.;Lucatello, Sara;Karakas, Amanda;Plez, Bertrand;Beers, Timothy C.;Christlieb, Norbert
Référence Memorie della Societa Astronomica Italiana, Supplementi - Journal of the Italian Astronomical Society, Supplement, 22, page (117-120)
Publication Publié, 2012

Article révisé par les pairs

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Résumé :

Carbon-enhanced metal-poor (CEMP) stars are believed to show the respective chemical imprints of more massive stars (M> 0.8M⊙) that are now extinct. In particular, it is expected that the observed abundance of Li should deviate in these stars from the standard Spite lithium plateau.We study here a sample of 11 metal-poor stars and a doublelined spectroscopic binary with -1.8 < [Fe/H] < -3.3 observed with VLT/UVES spectrograph. Among these 12 metal-poor stars, there are 8 CEMP stars for which we measure or constrain the Li abundance. In contrast to previous arguments, we demonstrate that an appropriate regime of dilution permits the existence of "Li-Spite plateau and C-rich" stars, whereas some of the "Li-depleted and C-rich" stars call for an unidentified additional depletion mechanism that cannot be explained by dilution alone. We found some evidence that rotation is related to depletion in some CEMP stars.