Galactic Chemical Evolution of the s Process from AGB Stars

TL;DR

This paper models the galactic chemical evolution of s-process elements from AGB stars, updating previous models with refined data and comparing results with spectroscopic observations across different metallicities.

Contribution

It provides an updated GCE model for s-process elements from AGB stars, incorporating new networks and refined AGB models, and assesses the combined s- and r-process contributions to solar system isotopes.

Findings

Reproduces observed abundance patterns of s-process elements at various metallicities.

Quantifies the s- and r-process contributions to solar system isotopes.

Discusses uncertainties in nucleosynthesis calculations.

Abstract

We follow the chemical evolution of the Galaxy for the s elements using a Galactic chemical evolution (GCE) model, as already discussed by Travaglio et al. (1999, 2001, 2004), with a full updated network and refined asymptotic giant branch (AGB) models. Calculations of the s contribution to each isotope at the epoch of the formation of the solar system is determined by following the GCE contribution by AGB stars only. Then, using the r-process residual method we determine for each isotope their solar system r-process fraction, and recalculate the GCE contribution of heavy elements accounting for both the s and r process. We compare our results with spectroscopic abundances at various metallicities of [Sr,Y,Zr/Fe], of [Ba,La/Fe], of [Pb/Fe], typical of the three s-process peaks, as well as of [Eu/Fe], which in turn is a typical r-process element. Analysis of the various uncertainties involved in these calculations are discussed.