Searching for Barium Enhancement in Two Blue Straggler Candidates of the M67 Open Cluster

Abstract Blue straggler stars are thought to be the outcome of interactions in binary systems, where mass transfer from a companion can lead to chemical enrichment. We analyzed the high-resolution HARPS spectra of two blue straggler candidates, NGC 2682 90 and NGC 2682 124, from the open cluster M67, to verify potential enhancement in s -process elements, as products of the previous Asymptotic Giant Branch phase of the donor. We determined atmospheric parameters with synthetic spectra, and derived abundances for Fe, C, Mg, Si, Ca, Ti, Cr, Mn, compatible with the abundances of the host cluster. We constrained precise Barium abundances using pymoog individual Ba ii line synthesis. While NGC 2682 90 exhibits no Barium enrichment ([Ba/Fe] = 0.20 ± 0.44), for NGC 2682 124 we estimated [Ba/Fe] = 0.64 ± 0.07, indicating detectable enrichment, contrary to previous studies.