Study of the Pulsations of the Semiregular Variable Stars

AST 0307281 Buchler，J. Robert不规则脉动星从所谓的W Vir型星延伸到RV Tau和半规则星，一直延伸到长周期Mira变星星星区。在这个项目中，一个彻底的，新颖的分析观测光变曲线数据和系统的数值模拟调查这些恒星的脉动特性正在进行中。这些明亮的变星在星星团和矮星系的观测研究中发挥着越来越重要的作用，这些星系可能很少有像经典造父变星这样的标准烛光。我们的目标是从不规则的光变曲线中提取独特的定量信息。一个测试也计划的假设，一个单一的共振机制是在这些恒星的不规则脉动的心脏。此外，这项研究将为这些恒星不确定的进化状态提供新的线索。新的观测数据，新的分析方法适用于非线性动力学，并在数值对流Hydrocodes的进展给予这项研究及时的地位。该项目具有更广泛的影响，因为正在开发的技术是非常有用的，以及在其他研究领域，从天文学到非线性动力学医学。因此，其中两个代码是用户友好和公开访问：TIFRAN，时间-频率分析，具有医疗应用程序作为诊断工具的语言障碍，耳鼻喉科和神经学等，和FLOWRECON，流量重建从一个时间序列与非线性动力学研究的广泛应用。在两名本科生的帮助下，正在建设一个关于径向和非径向脉动恒星的流行网站，并提供音频和视频。大型本科非微积分物理课的教学为研究人员提供了将天体物理学，特别是这项研究带到课堂的机会。

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.