We investigate systematically the dynamical mass ejection, r -process nucleosynthesis, and properties of electromagnetic counterparts of neutron-star (NS) mergers in dependence on the uncertain properties of the nuclear equation of state (EOS) by employing 40 representative, microphysical high-density EOSs in relativistic, hydrodynamical simulations. The crucial parameter determining the ejecta mass is the radius R 1.35 of a 1.35 M ☉ NS. NSs with smaller R 1.35 ("soft" EOS) eject systematically higher masses. These range from ∼10 −3 M ☉ to ∼10 −2 M ☉ for 1.35–1.35 M ☉ binaries and from ∼5 × 10 −3 M ☉ to ∼2 × 10 −2 M ☉ for 1.2–1.5 M ☉ systems (with kinetic energies between ∼5 × 10 49 erg and 10 51 erg). Correspondingly, the bolometric peak luminosities of the optical transients of symmetric (asymmetric) mergers vary between 3 × 10 41 erg s −1 and 14 × 10 41 erg s −1 (9 × 10 41 erg s −1 and 14.5 × 10 41 erg s −1 ) on timescales between ∼2 hr and ∼12 hr. If these signals with absolute bolometric magnitudes from −15.0 to −16.7 are measured, the tight correlation of their properties with those of the merging NSs might provide valuable constraints on the high-density EOS. The r -process nucleosynthesis exhibits a remarkable robustness independent of the EOS, producing a nearly solar abundance pattern above mass number 130. By the r -process content of the Galaxy and the average production per event the Galactic merger rate is limited to 4 × 10 −5 yr −1 (4 × 10 −4 yr −1 ) for a soft (stiff) NS EOS, if NS mergers are the main source of heavy r -nuclei. The production ratio of radioactive 232 Th to 238 U attains a stable value of 1.64–1.67, which does not exclude NS mergers as potential sources of heavy r -material in the most metal-poor stars.
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A 2013 study studied this question.