Can Neutron Star Mergers Alone Explain the r-process Enrichment of the Milky Way?

Abstract Comparing Galactic chemical evolution models to the observed elemental abundances in Milky Way, we show that neutron star mergers can be a leading r-process site only if at low metallicities such have very short delay times and significant ejecta masses are facilitated by of compact objects. Namely, black hole–neutron mergers, depending on hole spins, play an important role early enrichment Way. We also none binary population synthesis used this Letter, i.e., COMPAS, StarTrack, Brussels, ComBinE, BPASS, currently reproduce abundance observations. The predictions problematic not for but Type Ia supernovae, which may point shortcomings models.