Astronomy and Astrophysics, volume 496, 791-804 (2009/3-4)
High-resolution spectroscopic observations of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466.
PEREIRA C.B. and DRAKE N.A.
Abstract (from CDS):
We determined the atmospheric parameters and abundance pattern of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466 in order to better understand their evolutionary state and the nature of the s-element enhancement of these stars. We used high resolution optical spectroscopy. Atmospheric parameters and abundances were determined in the local-thermodynamic-equilibrium model atmospheres of Kurucz using the spectral analysis code MOOG. We conclude that HD 10613 is another metal-poor barium star with C/O=0.52 and [Fe/H]=-0.82, while BD+04°2466 is a CH star with C/O=3.6 and [Fe/H]=-1.92 rather than a metal-deficient barium star as it was previously classified. BD+04°2466 appears to be enriched in lead with [Pb/Ce]=+0.85 and [Pb/La]=+0.72. For BD+04°2466 the abundance of lead is in agreement with predictions from AGB models. Due to the low luminosity of these two stars, their observed s-process overabundance is better explained by mass-transfer in the past from an AGB star.