A Self-Consistent Bayesian Investigation of Star Cluster Binary Populations

银河系中大约三分之二的恒星是紧密成对的，称为“双星”。这些恒星中的许多都是在称为“星团”的大家庭中诞生的。然而，尽管双星是如此普遍和重要，关键问题仍然存在。研究人员将使用最新的观测结果和最先进的软件来建立一个关于双星及其主星团的经验特性的大型数据库。然后研究者将使用这个数据库来检验理论预测。这个数据库将通过一个定制的网站向公众开放，并将使天文社区能够进行许多后续研究。研究者还将指导最多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。该研究员将有助于推动一个更多样化、更复杂、更有竞争力的STEM劳动力队伍。研究者和他的团队将使用贝叶斯恒星演化分析（BASE-9）工具，在广泛的星团属性范围内，对数百个疏散星团中的双星群进行自我一致的表征。对于每个星团，研究者将收集来自Gaia、2MASS和Pan-STARRS的可用光度测量数据，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)建立星团的年龄、距离、变红和金属丰度，以及(c)推导逐星光度隶属度概率和质量。研究者将使用这个数据库来检查不同星团之间的双星频率和质量比分布的预测趋势（如年龄、金属丰度、密度、星团质量等的函数），如由恒星动力学和恒星形成模型预测的，以及在每个单独的星团内部（如与星团中心距离的函数），如由两体弛豫和质量分离效应预测的。研究人员还将开发一个自定义的在线交互式表和绘图工具，以提供对二进制和群集参数数据库的公共访问。与研究者一起工作的大多数学生将通过研究者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资助的本科生研究经验（REU）项目的一部分。除了指导的研究项目外，这些学生还将创建自己的研究网站，并帮助开发交互式网站，该网站将托管双星和星团数据库。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，该项目提供了许多专业发展研讨会，包括编码和高性能计算、科学传播和职业规划讨论。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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.