Collaborative Research: Open Clusters at the Interface of Stellar Evolution and Stellar Dynamics

长期以来，天文学家一直利用星团来了解结合在一起的恒星群的轨道运动，并将其作为测试恒星形成和恒星演化理论的实验室。动力学和恒星演化这两个领域是独立发展的，但随着探测器技术和计算速度的进步，现在有可能将这两个领域的研究结合起来。在这项合作研究中，Robert Mathieu博士（威斯康星大学麦迪逊分校）和Imants Platais博士（约翰霍普金斯大学）将进行一系列的观测和理论研究，以解决恒星演化和动力学中的几个突出问题。第一个目标是对7个年龄在1亿到70亿年之间的丰富疏散星团中的单星和双星种群进行全面的普查。这将通过精确测量微小的视切向运动和多历元测量径向速度来完成。这些数据将为整个进化的星系团提供高度可靠的三维运动学成员决定。第二个目标是描述这些星团中近100颗蓝离散星和其他新发现的异常恒星的种群特征，重点关注它们的双星、旋转和恒星活动分布。第三个目标是在对年轻星团观测的指导下，计算具有初始条件的疏散星团，特别是双星群的阵列恒星运动模拟。模拟将与J. Hurley博士（澳大利亚斯威本）和A. Sills博士（加拿大麦克马斯特）合作，通过碰撞产生异常恒星。结合大量不同年龄和质量的异常恒星的综合旋转、恒星活动和双星数据，将在恒星动力学和恒星演化的界面上对这些恒星的形成机制、内部结构和年龄有新的认识。这项研究计划将通过提高美国境内外未来天文学家的研究和教学技能，产生更广泛的影响。本研究将包括学生和一名博士后，预计将产生三篇研究生论文，几篇本科论文，以及暑期本科生的研究经验。这项工作将与研究、教学和学习的整合中心相关联，该中心是由Mathieu领导的NSF学习和教学中心。普拉泰斯通过他与台湾-波罗的海三边合作的联系，将协助最近处于不利地位的国家的学生和年轻研究人员的教育，培训和研究，这些国家拥有快速发展的基础设施和智力潜力。

Astronomers have long used stellar clusters to learn about the orbital motions of stars in bound groups and as laboratories for testing ideas of star formation and stellar evolution. The two fields of dynamics and stellar evolution have developed independently, but with advances in detector technology and computing speed, it is now possible to integrate these two areas of research.In this collaborative study, Dr. Robert Mathieu (University of Wisconsin - Madison) and Dr. Imants Platais (Johns Hopkins University) will undertake a series of observational and theoretical investigations to address several outstanding questions in stellar evolution and dynamics. The first objective is to obtain a comprehensive census of the single star and binary star populations in seven rich open clusters which have ages from 100 million to 7 billion years. This will be accomplished through precise measurements of minute apparent tangential motions and multi-epoch measurements of radial velocities. These data will provide highly reliable three-dimensional kinematic membership determinations for the entire evolved cluster population. The second objective is to characterize the populations of nearly 100 blue stragglers and other newly discovered anomalous stars in these clusters, focusing on their binary, rotation and stellar activity distributions. The third objective is to compute an array stellar motion simulations for open clusters with initial conditions, especially the binary population, guided by observations of young stellar clusters. The simulations will be performed in collaboration with Dr. J. Hurley (Swinburne, Australia), and Dr. A. Sills (McMaster, Canada) will collaborate on the production of anomalous stars through collisions. The union of comprehensive rotational, stellar activity and binary data for a large set of anomalous stars of different ages and masses will allow new insights on formation mechanisms, internal structures, and ages of these stars at the interface of stellar dynamics and stellar evolution.The research plan will have a broader impact through enhancement of the research and teaching skills of future astronomers, both within and beyond the borders of the United States. This research will include students and a postdoctoral fellow, and is expected to yield three graduate dissertations, several undergraduate theses, and research experiences of summer undergraduate students. This work will be associated with the Center for the Integration of Research, Teaching, and Learning, an NSF Center for Learning and Teaching directed by Mathieu. Platais, through his association with the trilateral Taiwan-Baltic collaboration, will assist in the education, training and research of students and young researchers in recently disadvantaged countries that have fast developing infrastructure and intellectual potential.