THE CH STARS .3. HEAVY ELEMENT ABUNDANCES

The s-process abundances in seven CH giants have been derived. Large enhancement of s-process elements relative to solar values are found, [s/Fe] = + 1.0 to + 2.0. In addition, the heavy s-process peak elements (Ba through Sm) are relatively more enhanced than the light s-process peak elements (Sr,Y,Zr), the average ratio of heavy-to-light s-process elements in the CH stars is + 0.9 dex. In addition, the abundance patterns are best fit by models in which seed nuclei are exposed to a single neutron irradiation instead of an exponentially decaying distribution of neutron exposures. These abundance patterns are explained best if the source of neutrons for the s-process material in CH stars is the (C(alpha,n)O)-C-13-O-16 reaction.