Nucleosynthesis Calculations for the Ejecta of Neutron Star Coalescences

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.

5 pages, 2 figures, proceedings of Nuclei in the Cosmos 2000, to be published in Nucl. Phys. A; minor correction

Cited by in corpus (11)

• Binary Neutron Star Mergers
• Radiative capture of nucleons at astrophysical energies with single-particle states
• Conformally Flat Smoothed Particle Hydrodynamics: Application to Neutron Star Mergers
• R-Process Nucleosynthesis in MHD Jet Explosions of Core-Collapse Supernovae
• Electromagnetic Dissociation as a Tool for Nuclear Structure and Astrophysics
• The NINJA-2 project: Detecting and characterizing gravitational waveforms modelled using numerical binary black hole simulations
• Nucleosynthesis in neutron-rich ejecta from quark-novae
• The 8Li(d,p)9Li Reaction and the Astrophysical 8Li(n,g)9Li Reaction Rate
• Coulomb dissociation of 9Li and the rate of the 8Li(n,g)9Li reaction
• Where and when: optimal scheduling of the electromagnetic follow-up of gravitational-wave events based on counterpart lightcurve models
• First Constraints on the Photon Coupling of Axion-like Particles from Multimessenger Studies of the Neutron Star Merger GW170817