Outflows from Short-Lived Neutron-Star Merger Remnants Can Produce a Blue Kilonova

Abstract

We present a 3D general-relativistic magnetohydrodynamic simulation of a short-lived neutron star remnant formed in the aftermath of a binary neutron star merger. The simulation uses an M1 neutrino transport scheme to track neutrino-matter interactions and is well-suited to studying the resulting nucleosynthesis and kilonova emission. We find that the ejecta in our simulations under-produce \(r\)-process abundances beyond the second \(r\)-process peak. For sufficiently long-lived remnants, these outflows \textit{alone} can produce blue kilonovae, including the blue kilonova component observed for AT2017gfo.