Study of the Pulsations of the Semiregular Variable Stars

不规则的脉动恒星从所谓的W Vir型恒星延伸到RV Tau和半规则恒星，一直延伸到长周期的Mira变星区。在这个项目中，对观测光曲线数据进行全面、新颖的分析，并对这些恒星的脉动特性进行系统的数值模拟调查。这些明亮的变星在星团和矮星系的观测研究中扮演着越来越重要的角色，在这些地方，像经典造父变星这样的标准烛光可能很少见。目标是从不规则的光曲线中提取独特的定量信息。科学家们还计划对这些恒星不规则脉动的核心存在单一共振机制的假设进行检验。此外，这项研究将为这些恒星不确定的演化状态提供新的线索。新的观测数据、新的非线性动力学分析方法和数值对流氢码的进展使这项研究具有及时的地位。该项目具有更广泛的影响，因为正在开发的技术在其他研究领域也非常有用，从天文学到非线性动力学再到医学。因此，有两种代码是用户友好的，并且可以公开访问：TIFRAN，时间频率分析，在医学上作为语言障碍、耳鼻喉科和神经病学等疾病的诊断工具，以及FLOWRECON，从时间序列中重建流，在非线性动力学研究中广泛应用。在两位本科生的帮助下，一个关于径向和非径向脉动恒星的音频和视频的流行网站正在建设中。大型本科非微积分物理课程的教学为研究者提供了将天体物理学，特别是本研究带入课堂的机会。

AST 0307281Buchler, J. RobertIrregularly pulsating stars stretch from the so-called W Vir type stars through the RV Tau and Semi-regular stars all the way into the long period Mira variable star region. In this project, a thorough, novel analysis of observational lightcurve data and a systematic numerical modeling survey of the pulsational properties of these stars is underway. These bright variable stars are playing an increasingly important role in the observational study of star clusters and dwarf galaxies where standard candles such as classical Cepheid variables may be rare. The goal is to extract unique, quantitative information from the irregular lightcurves. A test is also planned of the hypothesis that a single resonant mechanism is at the heart of the irregular pulsations of these stars. Further, the study will shed new light on the uncertain evolutionary status of these stars. New observational data, novel methods of analysis adapted from nonlinear dynamics, and progress in numerical convective hydrocodes lend this study a timely status.The project has a broader impact, because the techniques being developed are very useful in other research areas as well, ranging from astronomy to nonlinear dynamics to medicine. Thus two of the codes are being made user-friendly and publicly accessible: TIFRAN, the time-frequency analysis, that has medical applications as a diagnostic tool for speech disorders, otolaryngology and neurology among other things, and FLOWRECON, the flow reconstruction from a time-series with wide applications in nonlinear dynamics research. A popular website on radially and nonradially pulsating stars with audio and video is being constructed with the help of two undergraduate students. The teaching of the large undergraduate noncalculus physics class provides the investigator with the opportunity to bring astrophysics, and this research in particular, to the classroom.