Intermediate-mass main sequence stars have large radiative envelopes overlying convective cores. This configuration allows internal gravity waves (IGWs) generated at the convective-radiative interface to propagate towards the stellar surface. The signatures of these waves can be observed in the photometric and spectroscopic data from stars. We have studied the propagation of these IGWs using two-dimensional fully-non-linear hydrodynamical simulations with realistic stellar reference states from the one-dimensional stellar evolution code, Modules for Stellar Astrophysics (MESA). When a single wave is forced, we observe wave self-interaction. When two waves are forced, we observe non-linear interaction (i.e. triadic interaction) between these waves forming waves at different wavelengths and frequencies. When a spectrum of waves similar to that found in numerical simulations is forced, we find that the surface IGW frequency slope is consistent with recent observations. This power law is similar to that predicted by linear theory for the wave propagation, with small deviations which can be an effect of nonlinearities. When the same generation spectrum is applied to 3 solar mass models at different stellar rotation and ages, the surface IGW spectrum slope is very similar to the generation spectrum slope.

中文翻译：

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中等质量恒星辐射区内部重力波的二维模拟

中等质量的主序星具有覆盖在对流核心上的大辐射包络。这种配置允许在对流-辐射界面产生的内部重力波 (IGW) 向恒星表面传播。这些波的特征可以在恒星的光度和光谱数据中观察到。我们已经使用二维完全非线性流体动力学模拟研究了这些 IGW 的传播，这些模拟具有来自一维恒星演化代码、恒星天体物理学模块 (MESA) 的真实恒星参考状态。当单个波被强制时，我们观察到波的自相互作用。当两个波受力时，我们观察到这些波之间的非线性相互作用（即三元相互作用）形成不同波长和频率的波。当强迫类似于数值模拟中发现的波谱时，我们发现表面 IGW 频率斜率与最近的观察结果一致。该幂律类似于波传播的线性理论所预测的幂律，具有可能是非线性效应的小偏差。当相同的发生光谱应用于不同恒星旋转和年龄的3个太阳质量模型时，表面IGW光谱斜率与发生光谱斜率非常相似。