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arXiv · 1907.04872

Spiral-wave wind for the blue kilonova

Vsevolod Nedora·Sebastiano Bernuzzi·David Radice·Albino Perego·Andrea Endrizzi·Néstor Ortiz
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Abstract

The AT2017gfo kilonova counterpart of the binary neutron star merger event GW170817 was characterized by an early-time bright peak in optical and UV bands. Such blue kilonova is commonly interpreted as a signature of weak $r$-process nucleosynthesis in a fast expanding wind whose origin is currently debated. Numerical-relativity simulations with microphysical equations of state, approximate neutrino transport, and turbulent viscosity reveal a new mechanism that can power the blue kilonova. Spiral density waves in the remnant generate a characteristic wind of mass ${\sim}10^{-2}~M_{\odot}$ and velocity ${\sim}0.2$c. The ejected material has electron fraction mostly distributed above $0.25$ being partially reprocessed by hydrodynamic shocks in the expanding arms. The combination of dynamical ejecta and spiral-wave wind can account for solar system abundances of $r$-process elements and early-time observed light curves.

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Vsevolod Nedora, Sebastiano Bernuzzi, David Radice, Albino Perego, Andrea Endrizzi, Néstor Ortiz. 2019-07-10. Spiral-wave wind for the blue kilonova. https://doi.org/10.3847/2041-8213/ab5794

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