Issue |
A&A
Volume 447, Number 1, February III 2006
|
|
---|---|---|
Page(s) | 299 - 310 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20053182 | |
Published online | 27 January 2006 |
Li and Be depletion in metal-poor subgiants
1
Department of Astronomy and Space Physics, Uppsala University, Box 515, 751 20 Uppsala, Sweden e-mail: aegp@astro.uu.se; A.E.Garcia-Perez@open.ac.uk
2
European Southern Observatory, Karl-Schwarzschild Strasse 2, 85748 Garching bei München, Germany e-mail: fprimas@eso.org
Received:
3
April
2005
Accepted:
7
October
2005
A sample of metal-poor subgiants has been
observed with the UVES spectrograph at the Very Large Telescope
and abundances of Li and Be have been determined. Typical
signal-to-noise per spectral bin values for the co-added spectra are
of the order of 500 for the line (670.78 nm) and
100 for the
doublet lines (313.04 nm). The spectral
analysis of the observations was carried out using the Uppsala suite of
codes and marcs (1D-LTE) model atmospheres with stellar parameters
from photometry, parallaxes, isochrones and Fe ii lines. Abundance
estimates of the light elements were corrected for departures from
local thermodynamic equilibrium in the line formation. Effective
temperatures and Li abundances seem to be correlated and Be
abundances correlate with [O/H]. Standard models predict Li and Be
abundances approximately one order of magnitude lower than
main-sequence values which is in general agreement with the
observations. On average, our observed depletions seem to be 0.1 dex
smaller and between 0.2 and 0.4 dex larger (depending on which
reference is taken) than those predicted for Li and Be, respectively.
This is not surprising since the initial Li abundance, as derived from
main-sequence stars on the Spite plateau, may be systematically in
error by 0.1 dex or more, and uncertainties in the spectrum
normalisation and continuum drawing may affect our Be abundances
systematically.
Key words: stars: abundances / stars: atmospheres / stars: late type / stars: Population II
© ESO, 2006
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