Coordinated Global Time-Series Photometry of Variable Stars: the Whole Earth Telescope

AST-0205983PI Kawert经过几十年的发展，人们对恒星演化的许多阶段仍然知之甚少。这里的研究人员将利用大自然为探测恒星内部提供的一个强大工具，即星震学。在恒星演化的几个点上，恒星经历了自激的非径向脉动，这是可以观察到的多周期亮度变化。通过尽可能长时间地连续观察这些变化，它们解决了这些恒星中多种频率的变化。由于每个频率代表恒星的正常振荡模式，通过参考理论模型，他们将以惊人的细节推导出这些恒星的全球和内部结构的细节。其中，利用星震学，他们将非常精确地测量孤立脉动体的质量，确定脉动体内部结构或成分发生变化的位置，并对脉动体的化学成分进行限制或实际测量，作为半径的函数。这个项目的成功得益于一种独特的仪器--全地球望远镜(WET)的运行。WEAM是分布在地球各地的天文学家的国际合作伙伴关系，他们收集快速变化恒星的连续时间序列亮度测量结果，并分析这些数据，以提取其中包含的天体物理学见解。***

AST-0205983PI KawalerAfter decades of progress, many stages of stellar evolution remain only modestly understood. The investigators here will exploit a powerful tool that Nature provides for probing the interiors of stars, namely asteroseismology. At several points in their evolution, stars undergo self-excited nonradial pulsations, which are observable as multiperiodic brightness variations. By observing these variations as continuously as possible for as long as is practical, they resolve the multiple frequencies of variation in these stars. Since each frequency represents a normal-mode of oscillation of the star, by consulting theoretical models they will deduce details of the global and internal structure of these stars with striking detail. Among other things, using asteroseismology they will measure the mass of isolated pulsators to great accuracy, determine where there are structural or compositional changes in the interior of pulsators, and place limits on or actually measure the chemical composition of a pulsator as a function of radius. The success in this project results from the operation of a unique instrument known as the Whole Earth Telescope (WET). The WET is an international partnership of astronomers, distributed around the Earth, who gather continuous time-series brightness measurements of rapidly varying stars and analyze these data to extract the astrophysical insight contained therein. ***