Spiral-wave Wind for the Blue Kilonova
Abstract
The AT2017gfo kilonova (kN) counterpart of the binary neutron star merger event GW170817 was characterized by an early-time bright peak in optical and UV bands. Such blue kN 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 hydrodynamics-driven mechanism that can power the blue kN. Spiral density waves in the remnant generate a characteristic wind of mass ∼10-2 {M}⊙ and velocity ∼0.2 c. The ejected material has an 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2019
- DOI:
- 10.3847/2041-8213/ab5794
- arXiv:
- arXiv:1907.04872
- Bibcode:
- 2019ApJ...886L..30N
- Keywords:
-
- Neutron stars;
- Compact objects;
- Nucleosynthesis;
- R-process;
- Gravitational waves;
- 1108;
- 288;
- 1131;
- 1324;
- 678;
- Astrophysics - High Energy Astrophysical Phenomena;
- General Relativity and Quantum Cosmology
- E-Print:
- 5 pages, 4 figures