Research Projects

The project aims to explore the role of low to intermediate-mass stars (LIMS) at various metallicities in the production of heavy elements, particularly those heavier than iron. LIMS are identified as potential sites for the slow-neutron capture process, contributing to half of the heavy elements. Recently, proton ingestion episodes (PIEs) in very low-mass low-metallicity (TP) AGB stars have been identified as potential sites for the intermediate neutron capture process (i-process), responsible for the double enrichment of slow and rapid neutron capture elements in the CEMP-rs stars subgroup. The current understanding of the i-process restricts its occurrence in the low-metallicity regime. The project aims to investigate the dependence of i-process abundances on various AGB parameters such as metallicity, initial mass, and mixing processes. It will also unravel the formation mechanisms of double enriched stars at higher metallicities. A sample of rs stars at various metallicities is collected from preliminary analysis of their medium resolution spectra or publically available archives. High-resolution spectra (R~ 85000) are collected from different high-resolution spectrographs, and the abundances of all possible elements are derived. The detailed abundance profile will be compared with theoretical predictions from the i-process model with necessary modifications. The project expects to find a robust picture of the origin of rs enriched stars at various metallicities. If the i-process occurring at higher metallicities is the reason for these peculiar stars, it is a crucial constraint for Galactic Chemical Evolution (GCE) models.