ACOUSTIC WAVE GENERATION IN COLLAPSING MASSIVE STARS WITH CONVECTIVE SHELLS
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Date
2020
Authors
Abdikamalov, Ernazar
Foglizzo, Thierry
Journal Title
Journal ISSN
Volume Title
Publisher
Monthly Notices of the Royal Astronomical Society
Abstract
The convection that takes place in the innermost shells of massive stars plays an important
role in the formation of core-collapse supernova explosions. Upon encountering the supernova
shock, additional turbulence is generated, amplifying the explosion. In this work, we study how
the convective perturbations evolve during the stellar collapse. Our main aim is to establish
their physical properties right before they reach the supernova shock. To this end, we solve the
linearized hydrodynamics equations perturbed on a stationary background flow. The latter is
approximated by the spherical transonic Bondi accretion, while the convective perturbations
are modelled as a combination of entropy and vorticity waves. We follow their evolution from
large radii, where convective shells are initially located, down to small radii, where they are
expected to encounter the accretion shock above the proto-neutron star. Considering typical
vorticity perturbations with a Mach number ∼0.1 and entropy perturbations with magnitude
∼0.05kb/baryon, we find that the advection of these perturbations down to the shock generates
acoustic waves with a relative amplitude δp/γ p 10 per cent, in agreement with published
numerical simulations. The velocity perturbations consist of contributions from acoustic and
vorticity waves with values reaching ∼10 per cent of the sound speed ahead of the shock. The
perturbation amplitudes decrease with increasing and initial radii of the convective shells
Description
Keywords
Type of access: Open Access, hydrodynamics, Instabilities, shock waves
Citation
Abdikamalov, E., & Foglizzo, T. (2020). Acoustic wave generation in collapsing massive stars with convective shells. Monthly Notices of the Royal Astronomical Society, 493(3), 3496–3512. https://doi.org/10.1093/mnras/staa533