Nonlinear Stellar Pulsations

变星的研究是天文学的基础。 的 可变性的属性提供了比可以 从静态恒星中获得，它们对我们的 了解恒星的结构和演化，银河系 进化论和宇宙学 该项目涉及的建模 恒星不稳定性及其系统学。 一个新 非线性自适应水动力代码，产生更好的 模型和观测结果之间的一致性是 开发 这种新方法解决和跟踪重要的 在脉动周期中的物理特征。 本研究 新代码的结果将与先前PI的结果相结合 发展了脉动的半分析理论，以深入了解 机制。 将被考虑的恒星范围从 有规律变化的造父变星和天琴座RR型恒星， 金牛星和半正则变星。 随机性的影响 脉动噪声和随时间变化的分析方法 信号也将在比较的背景下进行研究， 理论结果与观察。

The study of variable stars is basic to much of astronomy. The properties of the variability provide more information than can be obtained from static stars and they contribute greatly to our understanding of stellar structure and evolution, galactic evolution and cosmology. This project concerns modelling of stellar instability and understanding its systematics. A new nonlinear adaptive hydrodynamic code which produces better agreement between the models and the observations has been developed. This new method resolves and tracks the important physical features during the pulsation cycle. In this study, the results from the new code will be combined with the PI's previously developed semi-analytical theory of pulsation to gain insights into the mechanisms. The stars which will be considered range from the regularly varying Cepheids and RR Lyrae stars to the erratic RV Tauri stars and Semi-regular variables. The effects of stochastic noise on pulsations and methods of analysis of time-dependent signals will also be studied in the context of comparing the theoretical results with observation.