Triple-star dynamics and the internal structure of low-mass stars

该项目将研究三星系统中的恒星，三星系统中有三颗恒星绕着一个共同的质心运行。这些系统的轨道会导致恒星在观测过程中相互遮挡或移动。恒星的运动将被用来确定它们的基本属性。该项目利用了三星系统中的恒星与我们的距离相同的事实，这使得确定它们的相对大小成为可能。恒星径向速度的后续光谱学和详细的建模用于确定绝对半径。三星系统有非常复杂的运动，这会随着时间的推移而改变它们的视亮度。该团队将对这些数据进行建模，以确定内部质量分布。他们将培训研究生工作的硕士学位和本科生工作的高级论文项目。研究人员还将把研究成果纳入他们的大学课程和公开讲座。这项工作将通过首次研究质量小于太阳的三体食双星的拱点运动来完成。拱点进动的速率与恒星内部的质量分布有关，研究小组将对此进行建模。他们将使用档案NASA开普勒使命光变曲线（光度时间序列）和光动力学计算机模型来测量拱点运动常数，这与星星内部的质量分布和浓度直接相关。这些常数将通过模拟恒星轨道周期的变化来确定。他们将使用多个地面望远镜获得的光谱来测量径向速度并确定标准恒星光球特征，例如有效温度、金属丰度、表面重力和旋转速度。他们将公开他们开发的数据集和工具，以模拟天文界的多个重叠日食事件，以及日食时间和径向速度测量。

This project will study the stars in triple-star systems, which have three stars orbiting a common center of mass. These systems have orbits which cause the stars to eclipse, or move in front of, eachother as seen during observation. The stars' movements will be used to determine their fundamental properties. The project takes advantage of the fact that the stars in a triple-star system are at the same distance from us, which makes it possible to determine their relative sizes. Follow-up spectroscopy of the stars' radial velocities and detailed modeling is used to determine absolute radii. Triple-star systems have very complicated motion, which changes their apparent brightness over time. The team will model these data to determine the internal mass distributions. They will train graduate students working on Master's degrees and undergraduate students working on senior thesis projects. The investigators will also incorporate research results into their college courses and public lectures. The work will be completed by examining, for the first time, the apsidal motion of three-body eclipsing binaries for stars less massive than the Sun. The rate of apsidal precession is related to the mass distribution inside the stars, which the team will model. They will use archival NASA Kepler mission lightcurves (photometric time series) and photo-dynamical computer models to measure the apsidal motion constants, which are directly related to the distribution and concentration of mass inside a star. The constants will be determined by modeling the changes in orbital period of the stars. They will use spectroscopy obtained at multiple ground-based telescopes to measure the radial velocities and determine the standard stellar photospheric characteristics, such as effective temperature, metallicity, surface gravity and rotational velocity. They will make publicly available the datasets and tools they developed to model multiple overlapping eclipse events for the astronomical community, as well as the eclipse times, and radial velocity measurements.