Nucleosynthesis calculations for the ejecta of neutron star coalescences

We present the results of fully dynamical r-process network calculations fo r the ejecta of neutron star mergers (NSMs). The late stages of the inspira l and the final violent coalescence of a neutron star binary have been calc ulated in detail using a 3D hydrodynamics code (Newtonian gravity plus back reaction forces emerging from the emission of gravitational waves) and a re alistic nuclear equation of state. The found trajectories for the ejecta se rve as input for dynamical r-process calculations where all relevant nuclea r reactions (including beta-decays depositing nuclear energy in the expandi ng material) are followed. We find that all the ejected material undergoes r-process. For an initial Y -e close to 0.1 the abundance distributions reproduce very accurately the s olar r-process pattern for nuclei with A > 130. For lighter nuclei strongly underabundant (as compared to solar) distributions are encountered. We sho w that this behaviour is consistent with the latest observations of very ol d, metal-poor stars, despite arguments that have recently been raised again st the possibility of NSM as possible sources of Galactic r-process materia l.