The Eu Isotopic Ratios in CEMP Stars

Abstract

Understanding the chemical evolution of galaxies requires accurate abundances of chemical elements in various stellar populations, which are then compared with theoretical predictions to probe their nucleosynthetic origin. However, most of the elements have several stable isotopes which are produced by different nucleosynthetic reactions, thus making multiple contributors to their overall abundance. The situation will be more complex in the case of heavy elements produced by different neutron capture processes. Hence, the abundances at the isotopic levels are more important to constrain the conditions at which the nucleosynthesis takes place and also to identify the actual isotopic path followed by the different neutron capture processes. This will help us identify the relative contribution of different neutron capture processes to the abundance of individual elements, and it is an essential ingredient of the GCE models. Moreover, the contribution of different astrophysical sites, such as AGB stars, to the overall chemical enrichment of our Galaxy can be estimated with greater accuracy. Here we present the preliminary results of our attempt to measure the Eu isotopic abundance in a sample of s-process-enhanced stars at various metallicities. The purpose of this analysis is primarily to demonstrate the feasibility of the technique and a detailed quantitative analysis will be presented in a future paper.