Speaker
Description
We investigate the nucleosynthesis and kilonova light curve based on recent long-term binary neutron star merger simulations that incorporate a two-moment neutrino-transport scheme. The ejecta are evolved for 30 days using axisymmetric radiation-hydrodynamics simulations coupled in-situ to a complete nuclear network. For the first time, we find that the neutrino-driven wind from the post-merger remnant is mostly proton-rich. The resulting nucleosynthesis products are predominantly ${}^{56}$Ni and other iron-group elements. After a few days, the decay of ${}^{56}$Ni and later ${}^{56}$Co becomes the primary source of heating in the expanding matter, which significantly alters the time dependence of the kilonova light curve. The observation of this effect would be a smoking gun for the presence of a long-lived neutron-star remnant in future kilonova observations.
