One-, Two-, and Three-dimensional Simulations of Oxygen-shell Burning Just before the Core Collapse of Massive Stars
One-, Two-, and Three-dimensional Simulations of Oxygen-shell Burning Just before the Core Collapse of Massive Stars
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DOI：
10.3847/1538-4357/ab2b9d
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
T. Yoshida;T. Takiwaki;K. Kotake;Koh Takahashi;K. Nakamura;H. Umeda
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文献类型：
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作者：
T. Yoshida;T. Takiwaki;K. Kotake;Koh Takahashi;K. Nakamura;H. Umeda
我们执行两个（2D）和三维（3D）对流氧壳燃烧的流体动力学模拟，发生在一个大规模的祖先星星的核心坍缩超新星内部深处。利用一维恒星演化程序，我们首先计算了初始质量为9-40 M的大质量恒星的演化。四个不同的超调参数，并在一维模型中得到了类似于以前的作品的CO核心质量的趋势。选择11个一维模型，有一个共存的硅和氧层，我们进行2D流体动力学模拟的演变为1000秒，直到核心崩溃的开始。我们发现，在具有108 cm尺度的Si/O层的模型中，获得了具有大尺度涡的对流，湍流马赫数为10.1，而大多数具有几×109 cm尺度的扩展O/Si层的模型表现出较低的湍流速度。我们的研究结果表明，具有厚的Si/O层的超新星祖先可以提供扰动辅助爆炸的首选条件。我们进行了一个25 M的湍流模型的3D模拟，其中表现出大规模的对流在2D模型。3D模型产生了与2D模型类似的大规模（λ = 2）对流;但是，湍流速度较低。通过估计的中微子发射特性的3D模型，我们指出，事件率的时间调制，如果在KamLAND和超神冈，可以提供重要的信息，在超新星前对流层的结构变化。
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 (ℓ = 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.