Résumé
We have carried out a new analysis of the very metal-poor CH/CN strong stars CS 22948-27 and CS 29497-34. In particular, the effective temperatures were recomputed by comparing newly obtained photometric data to colours derived from model atmospheres computed especially for these stars. Metallicities of [Fe/H] = -2.45 and -2.90 are found, respectively, for CS 22948-27 and CS 29497-34.
The abundances of heavy elements have been derived from newly obtained high-resolution spectroscopy in the blue spectral region, together with previously obtained spectra in the red, resulting in a total wavelength coverage of lambda lambda 4000-8200 Angstrom.
We find that the abundance patterns of our stars reflect enrichment by the r-process (as indicated by a high Eu abundance), as well as by the s-process, which could be due to a mass transfer episode from a companion crossing the AGE phase, although no clear evidence for binarity is indicated in the spectra obtained to date.