论文标题

在主序列中对波和核心对流的完全压缩模拟

Fully compressible simulations of waves and core convection in main-sequence stars

论文作者

Horst, L., Edelmann, P. V. F., Andrassy, R., Roepke, F. K., Bowman, D. M., Aerts, C., Ratnasingam, R. P.

论文摘要

语境。使用光谱方法在无弹性近似中进行了全明星模型中波产生和传播的最新非线性模拟。尽管它使长时间的步骤成为可能,但这种方法不包括声波的物理学完全,并且需要高度的人工粘度和热扩散率来进行数值稳定性。因此,与观测直接比较受到限制。目标。我们探索可压缩多维流体动力学代码SLH的功能,以模拟恒星振荡。方法。我们使用两个测试用例比较了2D SLH模拟中内部重力和压力波的一些基本特性,即线性波理论:(1)在BousSinesQ限制中的间隔重力波数据包,以及(2)具有带有激进核心和辐射式Envelope和辐射式ENVELOPE的现实$ 3 \ Mathrm {M} _ \ odot _ \ odot $ stellar $ stellar模型。在观察的背景下,还讨论了恒星模型的振荡特性。结果。我们的测试表明,在模拟恒星内部振荡时,需要专门的低操作技术。我们的模拟中内重力和压力波的基本特性与线性波理论非常吻合。与对同一恒星模型的无弹性模拟相比,我们可以遵循频率较低的内部重力波。速度和温度的时间频谱平坦,并且与观察到的巨大恒星的光谱兼容。结论。恒星振荡的流体动力学模拟可压缩方法是有希望的。我们的仿真耗散性较小,比可比的光谱模拟所需的发光度更低。完全可压缩的方法也可以研究重力和压力波的耦合。

Context. Recent, nonlinear simulations of wave generation and propagation in full-star models have been carried out in the anelastic approximation using spectral methods. Although it makes long time steps possible, this approach excludes the physics of sound waves completely and rather high artificial viscosity and thermal diffusivity are needed for numerical stability. Direct comparison with observations is thus limited. Aims. We explore the capabilities of our compressible multidimensional hydrodynamics code SLH to simulate stellar oscillations. Methods. We compare some fundamental properties of internal gravity and pressure waves in 2D SLH simulations to linear wave theory using two test cases: (1) an interval gravity wave packet in the Boussinesq limit and (2) a realistic $3\mathrm{M}_\odot$ stellar model with a convective core and a radiative envelope. Oscillation properties of the stellar model are also discussed in the context of observations. Results. Our tests show that specialized low-Mach techniques are necessary when simulating oscillations in stellar interiors. Basic properties of internal gravity and pressure waves in our simulations are in good agreement with linear wave theory. As compared to anelastic simulations of the same stellar model, we can follow internal gravity waves of much lower frequencies. The temporal frequency spectra of velocity and temperature are flat and compatible with observed spectra of massive stars. Conclusion. The low-Mach compressible approach to hydrodynamical simulations of stellar oscillations is promising. Our simulations are less dissipative and require less luminosity boosting than comparable spectral simulations. The fully-compressible approach allows the coupling of gravity and pressure waves to be studied too.

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