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Lithium abundances in CEMP stars
Masseron T., Johnson J.A., Lucatello S., Karakas A., PLEZ B. et al
The Astrophysical Journal / The Astrophysical Journal Letters 751 (2012) 14 - http://hal.archives-ouvertes.fr/hal-00690086
Planète et Univers/Astrophysique/Astrophysique stellaire et solaire
Physique/Astrophysique/Astrophysique stellaire et solaire
Lithium abundances in CEMP stars
T. Masseron, J. A. Johnson, S. Lucatello, A. Karakas, Bertrand PLEZ ()1, T. C. Beers, N. Christlieb
1 :  LUPM - Laboratoire Univers et Particules de Montpellier
CNRS : UMR5299 – Université Montpellier II - Sciences et techniques – IN2P3
Université de Montpellier II Place Eugène Bataillon - CC 72 34095 Montpellier Cédex 05
Astrophysique Stellaire
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.

The Astrophysical Journal / The Astrophysical Journal Letters
Articles dans des revues avec comité de lecture

62 pages, 16 figures, accepted for publication in ApJ

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