A Self-Consistent Bayesian Investigation of Star Cluster Binary Populations

在我们的银河系中，大约三分之二的恒星是成对的，也就是所谓的“双星”。这些恒星中有许多诞生于被称为“星团”的大家庭中。然而，尽管双星是多么常见和重要，关键的问题仍然存在。研究人员将使用新获得的观测和最先进的软件来建立一个大型的双星及其主星团的经验属性数据库。然后，研究人员将使用这个数据库来检查理论预测。该数据库将通过一个定制的网站向公众开放，并将使天文学界能够进行许多后续研究。这位调查员还将指导多达9名本科生。每个学生都将学习研究方法、编码、数据分析和网络开发方面的技能。研究人员将帮助推进一支更多样化、更复杂、更具竞争力的STEM工作队伍。研究人员和他的团队将使用恒星演化贝叶斯分析(BASE-9)工具，自我一致地描述数百个开放星团中的双星群，涉及广泛的星团属性。对于每个星团，研究人员将汇编来自GAIA、2MASS和PanSTARRS的现有测光数据，并在BASE-9软件中使用这些数据来(A)识别光度双星并确定它们的质量和质量比，(B)确定星团的年龄、距离、变红和金属丰度，以及(C)得出逐星光度成员的概率和质量。调查员将使用这个数据库来检查不同星系团的二进制频率和质量比分布的预测趋势(作为年龄、金属丰度、密度、星系团质量等的函数)。如恒星动力学和恒星形成模型所预测的，并且在每个单独的星系团内(例如，作为距离星系团中心的距离的函数)，如由二体驰豫和质量分离效应所预测的。调查员还将开发一个定制的在线互动表和绘图实用程序，使公众能够访问这个二进制和集群参数数据库。大多数与调查员合作的学生将通过调查员开发的现有网络从芝加哥地区招募，该网络是他在西北大学指导的NSF资助的本科生研究体验(REU)项目的一部分。除了指导研究项目外，这些学生还将创建自己的研究网站，并帮助开发将托管双星和星团数据库的互动网站。整个夏天，每个学生都将完全融入西北大学的天体物理学REU计划，该计划提供大量的专业发展研讨会，包括编码和高性能计算、科学交流和职业规划讨论。该奖项反映了NSF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。

About 2/3 of the stars in our galaxy reside in close pairs, called “binary stars”. Many of these stars are born within larger families known as “star clusters”. Yet despite how common and important binary stars are, vital questions remain. The investigator will use newly available observations and state-of-the-art software to produce a large database of the empirical properties of binary stars and their host star clusters. The investigator will then use this database to examine theoretical predictions. This database will be made publicly available through a custom website and will enable many follow-up studies by the astronomical community. The investigator will also mentor up to nine undergraduate. Each student will learn skills in research methods, coding, data analysis, and web development. The investigator will help to advance a more diverse, sophisticated, and highly competitive STEM workforce.The investigator and his team will self-consistently characterize the binary star populations in hundreds of open star clusters, across a wide range of cluster properties, using a Bayesian Analysis of Stellar Evolution (BASE-9) tool. For each cluster, the investigator will compile available photometry from Gaia, 2MASS and Pan-STARRS, and use these data within the BASE-9 software to (a) identify photometric binaries and determine their masses and mass ratios, (b) establish the cluster age, distance, reddening and metallicity, and (c) derive star-by-star photometric membership probabilities and masses. The investigator will use this database to examine predicted trends in binary frequency and mass-ratio distribution across different clusters (as functions of, e.g., age, metallicity, density, cluster mass, etc.) as predicted by stellar dynamical and star formation models, and within each individual cluster (e.g., as a function of distance from the cluster center) as predicted by two-body relaxation and mass segregation effects. The investigator will also develop a custom online interactive table and plotting utility that will provide public access to this database of binary and cluster parameters. Most students working with the investigator will be recruited from the Chicago area through an existing network that the investigator has developed as part of the NSF-funded Research Experiences for Undergraduates (REU) program he directs at Northwestern. In addition to the directed research projects, these students will also create their own research websites and help to develop the interactive website that will host the binary star and star cluster database. Over the summer, each student will be fully integrated into Northwestern’s astrophysics REU program, which provides numerous professional development workshops, including coding and high-performance computing, science communication and career planning discussions.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.