High-resolution spectroscopic observations of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466*
Observatório Nacional, Rua José Cristino, 77. CEP 20921-400, São Cristóvão, Rio de Janeiro-RJ, Brazil e-mail: email@example.com
2 Sobolev Astronomical Institute, St. Petersburg State University, Universitetski pr. 28, St. Petersburg 198504, Russia
Accepted: 11 January 2009
Aims. 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.
Methods. 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.
Results. 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.
Key words: stars: abundances / stars: chemically peculiar / stars: binaries: general
© ESO, 2009