Stellar Population Astrophysics (SPA) with the TNG: Beyond the iron peak: Galactic evolution of molybdenum, ruthenium, and zirconium through open clusters
Year: 2026
Type: article
Abstract: Context. Open clusters serve as key laboratories for studying the chemical evolution of the Milky Way. In particular, leveraging these coeval groups of stars to study elements beyond the iron peak provides insights into heavy-element nucleosynthesis, whose origins remain uncertain. Aims. This work aims to determine the Mo, Ru, and Zr abundances for 81 stars across 30 open clusters. We compare these new chemical patterns with those of key reference elements (Y, Sr, and Eu), which were previously derived by our group. This comparison seeks to disentangle the distinct contributions from various nucleosynthetic processes. Methods. Using the high-resolution spectra acquired within the Stellar Population Astrophysics programme using the HARPS-N echelle spectrograph at the Telescopio Nazionale Galileo, we estimated chemical abundances through spectral synthesis with TSFitPy under local thermodynamic equilibrium (LTE) conditions. Results. This study provides the first Ru abundances for a large open cluster sample, alongside new measurements for Mo and Zr. We observe tight correlations between Mo, Ru, and other s -process elements (Sr, Y, and Zr), with slopes near unity, suggesting common enrichment timescales. Conversely, relations with the r -process element Eu show significant deviations, implying additional nucleosynthetic contributions. Crucially, chemical planes involving [Mo/Ru] and [s/Mo] ratios suggest systematic offsets when compared to theoretical s -process predictions.
Source: Astronomy and Astrophysics
Institutions: University of Rome Tor Vergata, Centre National de la Recherche Scientifique, Université Côte d'Azur, Astronomical Observatory of Rome, Observatoire de la Côte d’Azur, National Institute for Astrophysics, McDonald Observatory, Saint Mary's University, Osservatorio di Astrofisica e Scienza dello Spazio, Odesa I. I. Mechnikov National University, Malmö University, Nordic Optical Telescope, Université Paris Cité, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, CY Cergy Paris Université, Osservatorio Astronomico di Padova, Konkoly Observatory, University of Bayreuth
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7202201649