论文标题
在AGB恒星和红色超级巨星的3D模拟中，自兴奋的脉动的特性
Properties of self-excited pulsations in 3D simulations of AGB stars and red supergiants
论文作者
论文摘要
凉爽巨人和超级巨人的特征变化归因于恒星搏动和大规模对流流的结合。完整的3D辐射流动力学建模是理解这些动力学过程性质的重要工具。近年来，我们的红色巨人3D模型网格中的参数空间已扩大。这些模型可以提供有关脉动的性质和特性的许多见解，包括对流和脉动之间的相互作用。我们处理类似于观察数据的渐近巨型分支（AGB）恒星（AGB）恒星和红色超级恒星的3D动力学模型。我们旨在探索恒星参数与自兴脉动的性质之间的关系。分析了使用CO5bold辐射流动力学代码计算出的全局“ Star-In-A-Box”模型的输出，特别是在脉动属性方面，以找到与输入和新兴恒星参数的可能相关性。将快速的傅立叶变换应用于球体平均的质量流，以识别模型恒星光球下方可能的径向脉动周期。研究了恒星参数与提取的脉动周期的相关性。我们发现，脉动周期与恒星参数与当前的预期吻合良好。脉动周期遵循Ritter的周期均值密度关系，我们的AGB模型与观察结果得出的周期稀疏关系一致。质量估计公式来自3D模型，将恒星质量与基本模式脉动周期和恒星半径相关。尽管自兴奋的脉动与自洽的对流之间的相互作用的非线性使分析变得复杂，但与当前的理论和观察性理解相对于当前的理论和观察性的理解而言，所产生的相关性非常吻合。
The characteristic variability of cool giants and supergiants is attributed to a combination of stellar pulsation and large-scale convective flows. Full 3D radiation-hydrodynamical modelling is an essential tool for understanding the nature of these dynamical processes. The parameter space in our 3D model grid of red giants has expanded in recent years. These models can provide many insights on the nature and properties of the pulsations, including the interplay between convection and pulsations. We treat 3D dynamical models of asymptotic giant branch (AGB) stars and red supergiants similar to observational data. We aim to explore the relation between stellar parameters and the properties of the self-excited pulsations. Output from global 'star-in-a-box' models computed with the CO5BOLD radiation-hydrodynamics code were analysed, particularly in regards to the pulsation properties, to find possible correlations with input and emergent stellar parameters. The fast Fourier transform was applied to spherically averaged mass flows to identify possible radial pulsation periods beneath the photosphere of the modelled stars. Stellar parameters were investigated for correlations with the extracted pulsation periods. We find that the pulsation periods varied with the stellar parameters in good agreement with the current expectations. The pulsation periods follow Ritter's period-mean density relation well and our AGB models agree with period-luminosity relations derived from observations. A mass estimate formula was derived from the 3D models, relating the stellar mass to the fundamental mode pulsation period and the stellar radius. While the non-linearity of the interplay between the self-excited pulsations and the self-consistent convection complicates analyses, the resulting correlations are in good agreement with respect to current theoretical and observational understandings.
