MINCE II. Neutron Capture Elements

The MINCE (Measuring at Intermediate metallicity Neutron-Capture Elements)project aims to gather the abundances of neutron-capture elements but also oflight elements and iron peak elements in a large sample of giant stars in thismetallicity range. T The aim of this work is to study the chemical evolution ofgalactic sub-components recently identified (i.e. Gaia Sausage Enceladus (GSE),Sequoia). We used high signal-to-noise ratios, high-resolution spectra andstandard 1D LTE spectrum synthesis to determine the detailed abundances. Wecould determine the abundances for up to 10 neutron-capture elements (Sr, Y,Zr, Ba, La, Ce, Pr, Nd, Sm and Eu) in 33 stars. The general trends of abundanceratios [n-capture element/Fe] versus [Fe/H] are in agreement with the resultsfound in the literature. When our sample is divided in sub-groups depending ontheir kinematics, we found that the run of [Sr/Ba] vs [Ba/H] for the starsbelonging to the GSE accretion event shows a tight anti-correlation. Theresults for the Sequoia stars, although based on a very limited sample, shows a[Sr/Ba] systematically higher than the [Sr/Ba] found in the GSE stars at agiven [Ba/H] hinting at a different nucleosynthetic history. Stochasticchemical evolution models have been computed to understand the evolution of theGSE chemical composition of Sr and Ba. The first conclusions are that the GSEchemical evolution is similar to the evolution of a dwarf galaxy with galacticwinds and inefficient star formation. Detailed abundances of neutron-capture elements have been measured inhigh-resolution, high signal-to-noise spectra of intermediate metal-poor stars,the metallicity range covered by the MINCE project. These abundances have beencompared to detailed stochastic models of galactic chemical evolution.