Three dimensional numerical simulation of mixing in supernova explosions

我们用二维流体力学程序计算了爆炸中的红色超巨星中Rayleigh-Taylor不稳定性的非线性增长，并考察了混合程度如何依赖于前体的核心质量和包络质量。结果与第II-P型超新星和最近的第II-b型超新星1993J的观测结果进行了比较。结果表明，第II-P型超新星光曲线的平台期取决于超新星喷出物中氢向内混合的程度。我们用二维流体动力学程序数值跟踪了爆炸中的红色超巨星中Rayleigh-Taylor(R-T)不稳定性的非线性增长，并检验了R-T混合是否足够大到足以解释II-P型超新星光曲线的平台长度。对于主序质量为o…的两个红超巨星模型，证实了氢以500-800 kms^-1&gt；的膨胀速度向核内混合SUN&GT；&GT；和SUN&GT；&GT；的F13 M_&lt；和20 M_&lt；。即使初始微扰的幅度很小，如-0.2%，氢的混合也足以重现光曲线的平台。然而，^&lt；56&gt；Ni的向外混合在两个祖先之间是如此不同。在太阳富氢的13颗恒星中，镍被混合到富氢包层的中间，而在太阳&>的20颗恒星中，镍几乎没有混合。这些混合的差异可能会影响光曲线的形状。有人认为，II-P型超新星光曲线平台期的持续时间取决于超新星喷出物中氢向内混合的程度。我们用二维流体动力学程序数值跟踪了爆炸中的红色超巨星中Rayleigh-Taylor(R-T)不稳定性的非线性增长，并检验了R-T混合是否足够大到足以解释II-P型超新星光曲线的平台长度。两个红超巨星模型的主序质量分别为SUN&GT；和SUN&GT；的13 M&lt；和SUN&GT；的20 M&lt；证实了氢以500-800 km^-1&gt；的膨胀速度向核心内混合。即使初始微扰的幅度很小，如-0.2%，氢的混合也足以重现光曲线的平台。然而，^&lt；56&gt；Ni的向外混合在两个祖先之间是如此不同。在太阳富氢的13颗恒星中，镍被混合到富氢包层的中间，而在太阳&>的20颗恒星中，镍几乎没有混合。混合中的这些差异可能会影响灯光曲线的形状。较少

We calculate a nonlinear growth of the Rayleigh-Taylor instability in the exploding red supergiant stars with a two-dimensional hydrodynamical code, and examine how the extent of mixing depends of the progenitor's core mass and the envelope mass. The results are compared with the observations of type II-P supernovae and the recent type II-b supernova 1993J.It has been suggested that the duration of the plateau of Type II-P supernova light curves depends on the extent of inward mixing of hydrogen in the supernova ejecta. We have followed numerically a nonlinear growth of the Rayleigh-Taylor (R-T) instability in the exploding red super-giant stars with a two-dimensional (2-D) hydro-dynamical code, and examined whether or not the R-T mixing is large enough to account for the plateau length of Type II-P supernova light curves. The inward mixing of hydrogen into the core at expansion velocities of 500-800kms^<-1> is confirmed for the two red-supergiant models with the main-sequence masses o … More f 13 M_<<of sun>> and 20 M_<<of sun>>. Mixing of hydrogen is extensive enough to reproduce the plateau of light curves even with a very small amplitude of the initial perturbations such as - 0.2%. However, the outward mixing of ^<56>Ni is so defferent between the two progenitors. The nickel is mixed up to the middle of the hydrogen-rich envelope in the 13 M_<<of sun>>, while it is hardly mixed for the 20 M_<<of sun>> stars. These differences in the mixing may affect the shape of light curves.It has been suggested that the duration of the plateau of Type II-P supernova light curves depends on the extent of inward mixing of hydrogen in the supernova ejecta. We have followed numerically a nonlinear growth of the Rayleigh-Taylor (R-T) instability in the exploding red super-giant stars with a two-dimensional (2-D) hydro-dynamical code, and examined whether or not the R-T mixing is large enough to account for the plateau length of Type II-P supernova light curves. The inward mixing of hydrogen into the core at expansion velocities of 500-800kms^<-1> is confirmed for the two red-supergiant models with the main-sequence masses of 13 M_<<of sun>> and 20 M_<<of sun>>. Mixing of hydrogen is extensive enough to reproduce the plateau of light curves even with a very small amplitude of the initial perturbations such as - 0.2%. However, the outward mixing of ^<56>Ni is so defferent between the two progenitors. The nickel is mixed up to the middle of the hydrogen-rich envelope in the 13 M_<<of sun>>, while it is hardly mixed for the 20 M_<<of sun>> stars. These differences in the mixing may affect the shape of light curves. Less