Using Recent Gravitational-wave Observations to Estimate the Contribution of Binary Neutron Star Mergers to R-process Enrichment

We aim to investigate r-process enrichment from binary neutron star mergers (BNS), supported by multi-messenger observations that include the 2025 Gravitational-Wave Transient Catalog (GWTC-4). Recent population analyses of these gravitational-wave events yield constraints on the rates and properties of BNS mergers. We additionally explore the impact of a semi-parametric neutron star equation of state (EoS), imposing nuclear theoretical and experimental constraints up to nuclear saturation density and combine information from observations of heavy pulsar masses, gravitational waves, and x-ray pulse profile modeling to constrain higher densities. Different EoSs produce distinct predictions for the ejecta mass of the mergers, which depends on the mass-radius relationship of neutron stars. Our analysis offers updated insight into the contribution of BNS mergers to r-process enrichment of galaxies like the Milky Way. We also discuss ongoing effort toward imposing these constraints into models of galactic chemical evolution.