2005A&A...441..303Z

An LTE abundance analysis based on high-resolution spectra is presented for the carbon-rich star BD+57° 2161, whose evolutionary status is unknown. With [C/Fe]=+0.4dex and a mean s-process overabundance of [s/Fe]≃+1.5 dex the peculiar atmospheric composition of BD+57° 2161 is confirmed. The ¹²C/¹³C abundance ratio was found to be about 10. The mild iron deficiency, [Fe/H]=-0.2, supports the idea that BD+57° 2161 could be an old-disk-population object. Radial-velocity measurements confirm the binary nature of the star. Therefore the peculiar chemical composition could be due to the mass transfer from the secondary - AGB star in the past. Orbital parameters are estimated for another star of this group, BD+75° 348.