Comprehensive Analysis of Period Changes in Eclipsing Binaries as a Probe of Stellar Astrophysics

双星是恒星形成过程的自然和非常常见的产物，它作为恒星大小、质量、温度和光度的校准器，为恒星研究提供了重要的基础。它们也是恒星结构、形成和演化、潮汐相互作用和其他更专业领域的探测器，如吸积物理、星震学、共振动力学和多个恒星系统中系外行星的形成和演化。食双星是一组特殊的双星，在双星中，两颗恒星周期性地相互遮挡，产生其光曲线的变化。SETI研究所和圣地亚哥州立大学的一组科学家将对这种特殊类型的双星进行偏离常规周期行为的分析。行星的存在、自转和潮汐作用力都会引起偏差。通过调查这些偏差，该团队将能够约束每一颗组成恒星的内部结构，为改进当前的恒星结构模型提供独特的约束。此外，该团队将与现有的国家教育推广项目合作，为STEM教师创建一系列为期3天的研讨会，这些项目是天文学家与3至9年级的教师合作的。这些研讨会将提供以日食和凌日为主要主题的动手项目学习。该项目计划包括三个部分：1)测量数百颗食双星几十年的周期变化；2)将每颗恒星的内部结构限制在合适的双星中；3)探测其他天体(恒星、环绕双星的行星)的存在。研究人员将使用地面和天基档案中的所有可用的光度学数据来研究数百颗已知的日食双星。此外，他们将使用最先进的建模代码，根据特定系统的轨道配置及其组件的属性，以及相应的潮汐和广义相对论效应，预测测量到的日食时间。目前，某些双星的周期变化被用来测量双星的平均近地运动常数。该项目有可能在更大的样本中测量每一颗恒星的近地运动常数。这将通过使用几十年来测量的日食时间来实现。这是至关重要的，因为进动时间标比双星的轨道周期长得多，因此，它们的探测通常需要跨越数十年的光度观测。研究覆盖不同恒星类型和环境的大样本食双星也将促进双星相互作用物理学的知识，从而更好地理解潮汐作用力、迁移、自旋-轨道耦合和质量转移。这一奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A natural and very common product of star formation processes, binary stars provide a vital foundation of stellar studies as calibrators for stellar sizes, masses, temperatures, and luminosities. They also serve as probes for stellar structure, formation and evolution, tidal interactions, and other more specialized fields such as accretion physics, asteroseismology, resonant dynamics, and the formation and evolution of exoplanets in multiple star systems. Eclipsing binaries are a special group of binary stars, in which the two stars periodically eclipse each other, producing variations in their light curves. A team of scientists at the SETI institute and at San Diego State University will perform an analysis of deviations from the regular, periodic behavior in this special type of binary stars. Deviations can be introduced by the presence of planets and by rotation and tidal forces. By investigating these deviations, the team will be able to constrain the internal structure of each component star, providing unique constraints to improve current stellar structure models. In addition, the team will create a set of 3-days workshops for STEM teachers, in collaboration with existing national education outreach programs that partner astronomers with teachers in grades 3 to 9. The workshops will provide hands-on project-based learning with an overarching theme of eclipses and transits. The project plan has three components: 1) Measure decades-long period changes for hundreds of eclipsing binaries; 2) Constrain the internal structure of each star in suitable binaries; 3) Probe for the presence of additional bodies (stars, circumbinary planets). The investigators will use all available photometric data from ground- and space-based archives for hundreds of known eclipsing binaries. Furthermore, they will use a state-of-the-art modeling code that predicts the measured eclipse times based on the orbital configuration of the particular system and the properties of its components, as well as on the corresponding tidal and general relativity effects. Presently, period changes in certain binaries are used to measure the average apsidal motion constant of the binary. This project has the potential to measure the apsidal motion constants of each star in a much larger sample. This will be made possible by using eclipse times measured over many decades. This is critical because the precession timescales are much longer than the orbital period of the binaries and, as a result, their detection often requires photometric observations spanning decades. Studying a large sample of eclipsing binaries covering different stellar types and environments will also advance the knowledge of the physics of binary interactions, leading to a better understanding of tidal forces, migration, spin-orbit coupling, and mass transfer.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.