Characterizing Galactic Neutron Capture Gradients with Open Clusters

Le résumé fourni par la source

The chemistry of stars provides powerful insight into the history of the Milky Way. With multiple large-sky spectroscopic surveys that are currently available, using chemistry as a means to study the evolution and history of the Milky Way and potentially characterize the ages of different stellar populations therein has flourished. Open clusters have long been used as landmarks to calibrate different age dating methods (e.g., gyrochronology and asteroseismology). In this work, we utilize the SDSS-IV/APOGEE-based Open Cluster Chemical Abundances and Mapping (OCCAM) survey as our foundation for new optical observations; enabling us to characterize neutron capture abundances for reliable cluster members. For 56 stars in 18 open clusters, we collect high-resolution (R > 50,000), high-S/N (>75 at 5500A), spectra from Keck I and Magellan Baade telescopes. With these data, we derive abundances for 23 elements using BACCHUS, including 7 neutron capture abundances not measurable by APOGEE. Finally, we use these neutron capture abundances to characterize the distribution of these elements radially in the Milky Way. We find that elements in the neutron-capture families exhibit significantly flatter gradients as compared to the lighter alpha and iron-peak elements. In addition, we find the abundance each of the elements exhibits large scatter and little mean variation through time. These results could indicate that the enrichers for the heavier elements are well-distributed throughout the Milky Way's thin disk or primarily occurred early on in the Milky Way's history.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.