Rb/Zr] ratio in Ba stars as a diagnostic of the companion AGB stellar mass

Abstract

Understanding the nucleosynthesis and evolution of Asymptotic Giant Branch (AGB) stars is of primary importance as they are the main producers of some of the key elements in the Universe. They are the predominant sites for the slow neutron-capture nucleosynthesis. The exact physical conditions and nucleosynthetic processes occuring at the interior of AGB stars are not clearly understood, that hinders a better understanding of the contribution of these stars to the Galactic chemical enrichment. The extrinsic stars, which are known to have received products of AGB phase of evolution via binary mass transfer mechanisms, form vital tools to trace the AGB nucleosynthesis. The [Rb/Zr] ratio is an important diagnostic to understand the average neutron density at the s-process site and provide important clues to the mass of the companion AGB stars. In this work we have presented the estimate of [Rb/Zr] ratios, based on the high resolution spectroscopic analysis for a sample of Ba stars, and discussed how it can be used to understand the characteristics of the AGB star. Results from an analysis based on parametric model to confirm the mass of the companion AGB star are also presented.