New analysis of the two carbon-rich stars CS22948-27 e CS29497-34: binarity and neutron capture elements

Autor(es)

Barbuy, B. ^[1] ; Spite, M. ; Spite, F. ; Hill, V. ; Cayrel, R. ; Plez, B. ; Petijean, P.

Afiliação do(s) autor(es)

^[1] Universidade de São Paulo (USP). Instituto de Astronomia, Geofísica e Ciências Atmosféricas - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Astronomy & Astrophysics; v. 429, n. 3, p. 1031-1042, 2005.
• Área do conhecimento: Ciências Exatas e da Terra - Astronomia
• Assunto(s): Galáxias Estrelas binárias

Resumo

We have carried out a new determination of abundances in the very metal-poor CH/CN strong stars CS 22948-27 and CS 29497-34, using high-resolution spectra obtained with the HARPS spectrograph at the 3.6 m telescope of ESO, La Silla, that covers the range $\lambda\lambda$ 4000-6900 Å at a resolution of R = 100.000. Both stars are found to be long period binaries. It is confirmed that the abundance patterns show an enhancement of the $\alpha$-elements (like Mg, Ca), of the proton capture elements (like Na and Al) and a strong enrichment in "r" and "s" process elements, where the s-enrichment is probably due to a mass transfer episode from a companion in its AGB phase. The possible origins of the abundance pattern and especially of the strong enhancement of both "s" and "r" elements are discussed. (AU)

• Processo FAPESP: 00/10406-4 - Evolução química e populações estelares da galáxia, nuvens de Magalhães e galáxias elípticas, através de espectroscopia e imageamento
• Beneficiário: Beatriz Leonor Silveira Barbuy
• Modalidade de apoio: Auxílio à Pesquisa - Temático