Available formats: HTML | PDF | (gzipped) PostScript
Heavy-element abundances in the CH/CN-strong very metal-poor stars CS 22948-27 and CS 29497-34 *
V. Hill 1,2,
B. Barbuy 3,
M. Spite 2,
F. Spite 2,
R. Cayrel 4,
B. Plez 5,
T.C. Beers 6,
B. Nordström 7 and
P.E. Nissen 8
Received 26 July 1999 / Accepted 2 November 1999
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 4000-8200 Å.
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 AGB phase, although no clear evidence for binarity is indicated in the spectra obtained to date.
Key words: stars: abundances stars: fundamental parameters stars: general
Send offprint requests to: B. Barbuy
Online publication: December 17, 1999