One-, Two-, and Three-dimensional Simulations of Oxygen-shell Burning Just before the Core Collapse of Massive Stars

• Published in: The Astrophysical journal Vol. 881; no. 1; pp. 16 - 35
• Main Authors: Yoshida, Takashi, Takiwaki, Tomoya, Kotake, Kei, Takahashi, Koh, Nakamura, Ko, Umeda, Hideyuki
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 10.08.2019; IOP Publishing
• Subjects: Astrophysics; Collapse; Computational fluid dynamics; Computer simulation; Convection; Eddies; Explosions; Fluid flow; Fluid mechanics; Hydrodynamics; Large-scale eddies; Mach number; Massive stars; Neutrinos; One dimensional models; Oxygen; Perturbation; Silicon; Simulation; stars: massive; Stellar evolution; Supernova; supernovae: general; Three dimensional models; Two dimensional models; Velocity
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.3847/1538-4357/ab2b9d

We perform two- (2D) and three-dimensional (3D) hydrodynamics simulations of convective oxygen-shell burning that takes place deep inside a massive progenitor star of a core-collapse supernova. Using a one-dimensional (1D) stellar evolution code, we first calculate the evolution of massive stars with an initial mass of 9-40 M . Four different overshoot parameters are applied, and a CO-core mass trend similar to previous works is obtained in the 1D models. Selecting eleven 1D models that have a coexisting silicon and oxygen layer, we perform 2D hydrodynamics simulations of the evolution for ∼100 s until the onset of core collapse. We find that convection with large-scale eddies and the turbulent Mach number of ∼0.1 is obtained in the models having a Si/O layer with a scale of 108 cm, whereas most models that have an extended O/Si layer up to a few ×109 cm exhibit lower turbulent velocity. Our results indicate that the supernova progenitors that possess a thick Si/O layer could provide the preferred condition for perturbation-aided explosions. We perform the 3D simulation of a 25 M model, which exhibits large-scale convection in the 2D models. The 3D model develops large-scale ( = 2) convection similar to the 2D model; however, the turbulent velocity is lower. By estimating the neutrino emission properties of the 3D model, we point out that a time modulation of the event rates, if observed in KamLAND and Hyper-Kamiokande, could provide important information about structural changes in the presupernova convective layer.