Magnetized 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. A magnetized wind is driven from the remnant and ejects neutron-rich material at a quasi-steady-state rate of 0.8 × 10 ^−1 M _⊙ s ^−1 . We find that the ejecta in our simulations underproduce r -process abundances beyond the second r -process peak. For sufficiently long-lived remnants, these outflows alone can produce blue kilonovae, including the blue kilonova component observed for AT2017gfo.

Keywords

• Transient sources
• Compact objects
• Neutron stars