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The metal–poor end of the Spite plateau

Published online by Cambridge University Press:  09 March 2010

L. Sbordone ,
P. Bonifacio ,
E. Caffau ,
H.-G. Ludwig ,
N. Behara ,
J. I. Gonzalez-Hernandez ,
M. Steffen ,
R. Cayrel ,
B. Freytag  and
C. Van't Veer
...Show all authors
L. Sbordone
Affiliation:
CIFIST Marie Curie Excellence Team GEPI – Observatoire de Paris – France
P. Bonifacio
Affiliation:
CIFIST Marie Curie Excellence Team GEPI – Observatoire de Paris – France INAF – Osservatorio Astronomico di Trieste – Italy
E. Caffau
Affiliation:
GEPI – Observatoire de Paris – France
H.-G. Ludwig
Affiliation:
CIFIST Marie Curie Excellence Team GEPI – Observatoire de Paris – France
N. Behara
Affiliation:
CIFIST Marie Curie Excellence Team GEPI – Observatoire de Paris – France
J. I. Gonzalez-Hernandez
Affiliation:
CIFIST Marie Curie Excellence Team GEPI – Observatoire de Paris – France Universidad Complutense de Madrid – Spain
M. Steffen
Affiliation:
Astrophysikalische Institut Pottsdam – Germany
R. Cayrel
Affiliation:
GEPI – Observatoire de Paris – France
B. Freytag
Affiliation:
Centre de Recherche Astrophisique de Lyon, UMR 5574 – France
C. Van't Veer
Affiliation:
GEPI – Observatoire de Paris – France
P. Molaro
Affiliation:
INAF – Osservatorio Astronomico di Trieste – Italy
B. Plez
Affiliation:
Université Montpellier 2 – France
T. Sivarani
Affiliation:
Indian Institute of Astrophysiscs, Bangalore – India
M. Spite
Affiliation:
GEPI – Observatoire de Paris – France
F. Spite
Affiliation:
GEPI – Observatoire de Paris – France
T. C. Beers
Affiliation:
Michigan State University and JINA, Lansing, MI – USA
N. Christlieb
Affiliation:
Landessternwarte Heidelberg – Germany
P. François
Affiliation:
GEPI – Observatoire de Paris – France
V. Hill
Affiliation:
GEPI – Observatoire de Paris – France Cassiopée, Observatoire de la Cote d'Azur, Nice – France
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Abstract

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We present the largest sample available to date of lithium abundances in extremely metal poor (EMP) Halo dwarfs. Four Teff estimators are used, including IRFM and Hα wings fitting against 3D hydrodynamical synthetic profiles. Lithium abundances are computed by means of 1D and 3D-hydrodynamical NLTE computations. Below [Fe/H]~−3, a strong positive correlation of A(Li) with [Fe/H] appears, not influenced by the choice of the Teff estimator. A linear fit finds a slope of about 0.30 dex in A(Li) per dex in [Fe/H], significant to 2–3 σ, and consistent within 1 σ among all the Teff estimators. The scatter in A(Li) increases significantly below [Fe/H]~−3. Above, the plateau lies at 〈A(Li)3D, NLTE〉 = 2.199 ± 0.086. If the primordial A(Li) is the one derived from standard Big Bang Nucleosynthesis (BBN), it appears difficult to envision a single depletion phenomenon producing a thin, metallicity independent plateau above [Fe/H] = −2.8, and a highly scattered, metallicity dependent distribution below.

Keywords

nuclear reactionsnucleosynthesisabundancesGalaxy: haloGalaxy: abundancesstars: abundancesstars: Population II
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S265: Chemical Abundances in the Universe: Connecting First Stars to Planets , August 2009 , pp. 75 - 76
Copyright
Copyright © International Astronomical Union 2010

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