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Nucleosynthesis Calculations for the Ejecta of Neutron Star Coalescences

S. Rosswog·C. Freiburghaus·F. -K. Thielemann
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Abstract

We present the results of fully dynamical r-process network calculations for the ejecta of neutron star mergers (NSMs). The late stages of the inspiral and the final violent coalescence of a neutron star binary have been calculated in detail using a 3D hydrodynamics code (Newtonian gravity plus backreaction forces emerging from the emission of gravitational waves) and a realistic nuclear equation of state. The found trajectories for the ejecta serve as input for dynamical r-process calculations where all relevant nuclear reactions (including beta-decays depositing nuclear energy in the expanding material) are followed. We find that all the ejected material undergoes r-process. For an initial Ye close to 0.1 the abundance distributions reproduce very accurately the solar r-process pattern for nuclei with A above 130. For lighter nuclei strongly underabundant (as compared to solar) distributions are encountered. We show that this behaviour is consistent with the latest observations of very old, metal-poor stars, despite simplistic arguments that have recently been raised against the possibility of NSM as possible sources of Galactic r-process material.

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S. Rosswog, C. Freiburghaus, F. -K. Thielemann. 2000-12-09. Nucleosynthesis Calculations for the Ejecta of Neutron Star Coalescences. https://doi.org/10.1016/s0375-9474(01)00724-2

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