用于M型渐近巨星分支恒星的DARWIN模型的广泛网格II.脉动周期对风属性的影响
An extensive grid of DARWIN models for M-type AGB stars II. Effects of pulsation periods on wind properties
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中文总结 AI 辅助
研究M型AGB恒星脉动周期对风属性的影响，通过比较基于经验P-L关系与周期-平均密度关系的DARWIN模型，发现风属性与\(L_*/M_*\)相关，周期影响大气动力学，周期-平均密度关系利于模型与观测比较。
中文摘要 AI 辅助
渐近巨星分支（AGB）恒星的质量损失是脉动、大气动力学、尘埃形成和辐射加速之间复杂相互作用的结果。脉动周期是动态大气和风模型的关键输入，基于恒星参数分配周期的不同规定可能导致预测风属性的系统差异。为更好地约束这一关键参数，我们通过比较基于经验周期-光度（P-L）关系的模型与采用从三维脉动模型导出的周期-平均密度关系的相应模型，研究了脉动周期的选择如何影响M型AGB恒星动态大气和风模型的风属性。我们分析了两个覆盖当前恒星质量、光度和有效温度范围的DARWIN模型网格。对于每个网格，使用P-L关系或周期-平均密度关系分配脉动周期，以便直接比较仅因周期不同而产生的成对模型的动态结构和风属性。无论采用何种周期规定，时间平均风属性都与\(L_*/M_*\)密切相关。脉动周期通过冲击传播和尘埃形成的相对时间变化影响大气动力学，进而影响风的形成和风属性。较短的周期有利于风的开始，仅脉动周期不同的模型可表现出显著不同的风属性。周期-平均密度关系通过考虑光度以外的恒星参数，为经验P-L关系提供了一种基于物理的替代方案，并使DARWIN模型与观测到的米拉变星之间能进行更直接的比较。
英文摘要
Mass loss from asymptotic giant branch (AGB) stars is the result of a complex interplay between pulsation, atmospheric dynamics, dust formation, and radiative acceleration. Pulsation periods are a key input in dynamical atmosphere and wind models, and different prescriptions for assigning periods based on stellar parameters may lead to systematic differences in the predicted wind properties. To better constrain this critical parameter, we investigated how the choice of pulsation period affects the wind properties of dynamical atmosphere and wind models of M-type AGB stars by comparing models based on an empirical period-luminosity (P-L) relation with corresponding ones that adopt a period-mean density relation derived from 3D pulsation models. We analysed two grids of DARWIN models that cover a range of current stellar masses, luminosities, and effective temperatures. For each grid, pulsation periods were assigned using either the P-L relation or the period-mean density relation, allowing for a direct comparison of the resulting dynamical structures and wind properties for pairs of models differing by period only. Independent of the adopted period prescription, the time-averaged wind properties correlate strongly with $L_\star/M_\star$. The pulsation period affects the atmospheric dynamics through changes in the relative timing of shock propagation and dust formation, which affect both wind formation and the resulting wind properties. Shorter periods favour the onset of a wind, and models differing only in pulsation period can exhibit significantly different wind properties. The period-mean density relation provides a physically motivated alternative to the empirical P-L relation by accounting for stellar parameters beyond luminosity, and enables a more direct comparison between DARWIN models and observed Mira variables.
