Heavy-element abundances in the CH/CN-strong very metal-poor stars CS 22948-27 and CS 29497-34

Citation
V. Hill et al., Heavy-element abundances in the CH/CN-strong very metal-poor stars CS 22948-27 and CS 29497-34, ASTRON ASTR, 353(2), 2000, pp. 557-568
Citations number
63
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
00046361 → ACNP
Volume
353
Issue
2
Year of publication
2000
Pages
557 - 568
Database
ISI
SICI code
0004-6361(200001)353:2<557:HAITCV>2.0.ZU;2-L
Abstract
We have carried out a new analysis of the very metal-poor CH/CN strong star s CS 22948-27 and CS 29497-34. In particular, the effective temperatures we re recomputed by comparing newly obtained photometric data to colours deriv ed from model atmospheres computed especially for these stars. Metallicitie s 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 previou sly obtained spectra in the red, resulting in a total wavelength coverage o f 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-proces s, 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.