The chemical composition of the rare J-type carbon stars
Abstract
Description
Abundances of lithium, heavy elements and carbon isotope ratios have been derived in 12 J-type galactic carbon stars. The abundance analysis shows that in these stars the abundances of s-process elements with respect to the metallicity are nearly solar. Tc is not present in most of them. The Rb abundances, obtained from the resonance 7800 Å RbI line, are surprisingly low, probably due to stroong non-LTE effects. Lithium and $^{13}$C are found to be enhanced in all the stars. These results are used to discuss the origin of J-stars.
8 pages, 2 figures, 1 table. Presented in "The Abundances Changes in AGB Stars", Mem. Soc. Astr. It., Monte Porzio, Italia 1999. Needs memsait.sty
8 pages, 2 figures, 1 table. Presented in "The Abundances Changes in AGB Stars", Mem. Soc. Astr. It., Monte Porzio, Italia 1999. Needs memsait.sty