Enzo Maiorca

Title: 
The s-element evolution in the galactic disk. The role of open clusters and the new s process scenario.

Abstract: 
Recent determinations of s element abundances in several open clusters have shown the neutron capture element evolution during the last 4 Gyr. The result was not predicted by the old s process nucleosynthesis scenario. We therefore calculated new s element yields from very low mass AGB stars. With them, we could reproduce the observed evolution with our galactic chemical evolutionary model. The new s process scenario foresees a large contribution from AGB stars with masses below 1.5 Msun, unconsidered in the previous scenario and this unexpectedly provides also a better description of the solar s element distribution, without the requirement of further nuclear processes.