Lithium abundances in CEMP stars

T. Masseron J. A. Johnson S. Lucatello A. Karakas Bertrand Plez 1 T. C. Beers N. Christlieb
1 Astrophysique Stellaire
LUPM - Laboratoire Univers et Particules de Montpellier
Abstract : Carbon-enhanced metal-poor (CEMP) stars are believed to show the chemical imprints of more massive stars (M > 0.8 Msun) 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 double-lined 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 find evidence that rotation is related to the Li depletion in some CEMP stars. Additionally, we report on a newly recognized double-lined spectroscopic binary star in our sample. For this star, we develop a new technique from which estimates of stellar parameters and luminosity ratios can be derived based on a high-resolution spectrum alone, without the need for input from evolutionary models.
Type de document :
Article dans une revue
The Astrophysical journal letters, Bristol : IOP Publishing, 2012, 751, pp.14
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Soumis le : samedi 21 avril 2012 - 08:39:36
Dernière modification le : jeudi 11 janvier 2018 - 06:26:27

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  • HAL Id : hal-00690086, version 1
  • ARXIV : 1203.3295



T. Masseron, J. A. Johnson, S. Lucatello, A. Karakas, Bertrand Plez, et al.. Lithium abundances in CEMP stars. The Astrophysical journal letters, Bristol : IOP Publishing, 2012, 751, pp.14. 〈hal-00690086〉



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