A Self-Consistent Bayesian Investigation of Star Cluster Binary Populations

在我们的星系中，大约有2/3的恒星是紧密成对的，称为“双星”。这些恒星中有许多诞生于被称为“星星团”的大家族中。然而，尽管双星是多么常见和重要，重要的问题仍然存在。研究人员将利用最新的观测结果和最先进的软件，建立一个关于双星及其宿主星星团的经验性质的大型数据库。然后，研究人员将使用该数据库来检查理论预测。该数据库将通过一个定制网站向公众开放，并将使天文学界能够开展许多后续研究。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Web开发方面的技能。该研究员将帮助推动一支更加多样化、复杂和具有高度竞争力的STEM队伍。研究员和他的团队将使用恒星演化贝叶斯分析（BASE-9）工具，在数百个开放星星集群中，在广泛的集群属性上，自洽地描述双星星星种群的特征。对于每个星团，研究人员将汇编来自盖亚、2 MASS和Pan-STARRS的现有测光数据，并在BASE-9软件中使用这些数据（a）识别测光双星并确定它们的质量和质量比，（B）确定星团年龄、距离、红化和金属丰度，（c）推导逐颗星星的测光成员概率和质量。研究人员将使用该数据库来检查不同聚类中二进制频率和质量比分布的预测趋势（作为以下各项的函数，例如，年龄、金属丰度、密度、星团质量等）如恒星动力学和星星形成模型所预测的，并且在每个单独的星团内（例如，作为离团簇中心的距离的函数），如通过两体弛豫和质量分离效应所预测的。研究人员还将开发一个定制的在线交互式表格和绘图实用程序，将提供公众访问这个数据库的二进制和集群参数。大多数学生与调查员将从芝加哥地区通过现有的网络，调查员已经开发了作为NSF资助的本科生研究经验（REU）计划的一部分，他在西北部。除了直接的研究项目，这些学生还将创建自己的研究网站，并帮助开发互动网站，将托管双星星和星星集群数据库。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项目，该项目提供众多专业发展研讨会，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价值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.