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

这个项目将研究三星系统中的恒星，这些系统中有三颗恒星绕着一个共同的质心运行。从观测过程中可以看到，这些星系的运行轨道使恒星相互遮挡或在其前面运行。恒星的运动将被用来确定它们的基本性质。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。使用恒星径向速度的后续光谱分析和详细建模来确定绝对半径。三星系统有非常复杂的运动，这会随着时间的推移改变它们的表观亮度。该团队将对这些数据进行建模，以确定内部质量分布。他们将培养硕士研究生和从事高级论文项目的本科生。调查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检查质量小于太阳的恒星的三体食双星的近地运动来完成。近地进动的速度与恒星内部的质量分布有关，该团队将对此进行建模。他们将使用存档的NASA开普勒任务光曲线(光度时间序列)和光动力学计算机模型来测量近地运动常数，这些常数与恒星内部质量的分布和集中直接相关。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，并确定标准的恒星光球层特征，如有效温度、金属丰度、表面重力和自转速度。他们将公开他们开发的数据集和工具，以便为天文学社区模拟多个重叠的日食事件，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.