后AGB脉动中的功率平衡与异常交换
Power balance and anomalous exchange in post-AGB pulsations
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中文总结 AI 辅助
本文为恒星脉动建立复平衡关系，应用于后AGB包层径向脉动，揭示异常交换模式中He II电离区与Z凸起的主要交换，并分类脉动谱区域。
中文摘要 AI 辅助
我们为恒星脉动建立了一个复平衡关系，其实部和虚部给出了激发率和振荡频率的配对关系。该公式包含热力学交换、边界功率以及惯性项、压缩项、水平面积项和引力分层项，且不假设弱非绝热性。应用于包层部分时，它利用完整脉动问题的本征频率和本征函数提供累积诊断。我们表明，可忽略的全局边界贡献可以与显著的内部边界功率共存，后者可能在很大程度上补偿包层内的热力学交换。对后AGB包层径向脉动的应用展示了普通模式、奇异模式和异常交换模式的这种行为。后者具有负的有效范数，净交换功率和激发率的符号相反。对于选定的激发异常模式，主要交换发生在He II电离区和Z凸起之间，外层电离层的参与程度低于比较模式。按最大响应范数分类揭示了所检查脉动谱中的不同区域。选定的异常分支在其从阻尼到激发的转变过程中保持水平面积主导性。
英文摘要
We develop a complex balance relation for stellar pulsations whose real and imaginary parts give paired relations for the excitation rate and oscillation frequency. The formulation includes thermodynamic exchange, boundary power, and the inertial, compression, horizontal-area, and gravitational-stratification terms, without assuming weak nonadiabaticity. Applied to portions of an envelope, it provides cumulative diagnostics evaluated using the eigenfrequency and eigenfunctions of the complete pulsation problem. We show that a negligible global boundary contribution can coexist with substantial internal boundary power, which may largely compensate the thermodynamic exchange within the envelope. Applications to radial pulsations of post-AGB envelopes illustrate this behaviour for ordinary, strange, and anomalous-exchange modes. The latter have a negative effective norm and opposite signs of net exchange power and excitation rate. For a selected excited anomalous mode, the principal exchange occurs between the He II ionization region and the Z-bump, with less participation from the outer ionization layers than in the comparison modes. Classification by the largest response norm reveals distinct domains across the examined pulsation spectrum. The selected anomalous branch retains horizontal-area dominance across its transition from damping to excitation.
