First Imaging Survey of Rapid Rotators and Be Stars with Long-Baseline Interferometry

这个项目的动机来自于干涉光学望远镜和红外望远镜最近的结果，这些望远镜已经开始解析快速旋转的恒星的表面。最近的恒星模型表明，旋转的影响远非可以忽略不计，并且可以影响快速旋转恒星的寿命、表面亮度、表面丰度和演化轨迹。在这里，研究人员将利用一种新仪器——密歇根红外合成器（MIRC），该仪器于去年在乔治亚州立大学高角分辨率天文学中心的6望远镜光学干涉仪上投入使用。有了它，他们将调查快速旋转恒星的表面，直接绘制重力变暗与纬度的关系，并测试此类恒星的冯·齐佩尔-罗氏模型。通过对光谱线轮廓、光谱能量分布和干涉测量可见性/闭合相位的详细建模，建立了恒星光球扁率和重力暗化规律的定量模型。这项工作将与最近的模型进行比较，以首次约束热恒星的内部结构和微分旋转的性质。最后，Be星盘的连续发射也将被成像，当与发射线测量和光谱能量分布相结合时，将允许构建迄今为止最精确的盘模型。目标是确定磁盘的温度结构和密度，并将这些属性与形成机制联系起来。这里的工作将成为一名研究生的博士论文，他将接受最前沿天文仪器使用方面的培训。通用分析工具和成像算法将公开提供给其他研究人员使用。还将开展一项以红外成像技术为中心的教育和公众宣传计划，包括通过安娜堡动手博物馆组织的一系列巡回展览。

This project is motivated by recent results from interferometric optical and infrared telescopes that have begun to resolve the surfaces of rapidly rotating stars. Recent stellar models have demonstrated that the effects of rotation are far from negligible and can influence the lifetimes, surface brightnesses, surface abundances, and evolutionary tracks of rapidly rotating stars. Here, the investigators will take advantage of a new instrument, the Michigan Infrared Combiner (MIRC), which was commissioned last year at the Georgia State University Center for High Angular Resolution Astronomy's 6-telescope optical interferometer. With it, they will survey the surfaces of fast rotating stars, directly mapping the latitude-dependence of gravity darkening and testing the von Zeipel-Roche model for such stars. Through detailed modeling of the line profiles, spectral energy distributions, and interferometry visibilities/closure phases, quantitative models of the stellar photospheres' oblateness and gravity darkening laws will be developed. This work will be compared to the recent models to constrain the internal structure and nature of differential rotation in hot stars for the first time. Finally, the continuum emission of Be star disks will also be imaged, which when combined with emission line measurements and the spectral energy distribution, will allow the construction of the most accurate disk models to date. The goal is to determine the temperature structure and density of the disks and to link these properties back to the formation mechanism.The work here will form the Ph.D. thesis of a graduate student who will be trained in the use of forefront astronomical instrumentation. The general purpose analysis tools and imaging algorithms will be made publicly available for use by other researchers. An education and public outreach program will also be undertaken which will center around infrared imaging technology, including a series of traveling exhibits organized through the Ann Arbor Hands-on Museum.