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

TL;DR

This paper uses advanced simulations to show that short-lived neutron star remnants can produce ejecta capable of generating blue kilonovae, matching observations like AT2017gfo.

Contribution

It introduces a 3D general-relativistic MHD simulation with neutrino transport to study kilonova ejecta from neutron star remnants, highlighting their role in blue kilonova production.

Findings

Ejecta under-produce r-process elements beyond the second peak.

Long-lived remnants can produce blue kilonovae.

Simulation results match observed features of AT2017gfo.

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.