The Formation, Evolution, and Fate of Multiple Star Systems

恒星诞生于稠密的气体云中，这些气体云在自身引力的作用下坍缩。有时会形成孤立的恒星，就像我们的太阳。但是，恒星也通常形成在受引力约束的双星或多星系统中。目前尚不清楚大多数双星是如何形成的。它们可能形成的一种方式是在新生恒星周围形成的气体和尘埃盘中。它们也可能一开始是分开形成的，后来由于彼此的引力而结合在一起。形成双星系统的数量，它们之间的距离，以及双星形成的环境都必须加以研究，以理解为什么它们如此普遍。研究人员试图通过发现和检查以前未知的新生双星来了解双星的形成。这些新生恒星将由美国国家科学基金会的甚大阵列（VLA）和阿塔卡马大型毫米/亚毫米阵列（ALMA）射电望远镜观测。这些高分辨率的观测将发现双星形成时的距离比我们太阳系的大小还小。它们将展示双星在哪里形成，它们最有可能是如何形成的，以及它们是否会在双星系统中度过一生。这个项目将有助于揭示像我们这样的太阳系围绕一颗恒星运转的频率。作为该项目的一部分，射电天文学将被整合到俄克拉荷马大学的本科和研究生教育中。使用当地3米射电望远镜的实验室活动将被设计为实现多层次的教育目标。与当地高中的合作也将使他们能够在教室里进行射电天文观测。研究人员将对多颗恒星进行系统的搜索。研究人员将分析猎户座和英仙座恒星形成区域的调查，总共采样超过400颗原恒星，获得超过30天文单位的分辨率。猎户座和英仙座之间的伴星距离分布将在它们之间进行比较，并与使用统计测试测量的野星分布进行比较。对于系统的一个子集，ALMA的分子线成像将用于验证磁盘是否属于开普勒，并测量原恒星的质量并估计它们的质量比。最后，即使系统没有伴星，但有一个干净的磁盘，也要评估它们以后出现碎片的可能性。除了这个普查，他们的形成条件将被描述和潜在的伴生地层将被估计。研究人员将更清晰地描绘出早期恒星形成时的多重性，以及随着恒星系统向主序成熟，多重恒星的分布必须如何变化。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。

Stars are born within clouds of dense gas that collapse under their own gravity. Sometimes solitary stars form, like our own Sun. But, stars also commonly form in binary or multiple star systems that are bound by gravity. It remains unknown how most of these binary stars form. One way that they may form is within the disk of gas and dust that forms around the newborn star. They may also first form separately and later become bound due to their own mutual gravity. The number offorming binary systems, their separations, and the environment that the binary stars formed within must be examined to understand why they are so common.The investigators seek to understand formation of binary stars, by finding and examining previously unknown newborn binary stars. These newborn stars will be observed with the NSF's Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescopes. These high-resolution observations will discover binary stars forming with separations smaller than the size of our own Solar System. They will show where binary stars form, how they most likely formed, and if they will remain in a binary system throughout their lives. This project will help reveal how often Solar Systems like our own form around a single star. As part of this project, radio astronomy will be integrated into undergraduate and graduate education at the University of Oklahoma. Lab activities using the local 3-meter radio telescope will be designed to fulfill educational goals at multiple levels. Collaboration with local high schools will also enable them to conduct radio astronomy observations from their classroom.The investigators will conduct a systematic search for multiple stars. The investigators will analyze surveys of the Orion and Perseus star forming regions, sampling over 400 proto-stars in total, achieving better than 30 Astronomical Unit resolution. The companion separation distributions between Orion and Perseus will be compared between themselves and with the distributions measured for field stars using statistical tests. For a subset of the systems, molecular line imaging from ALMA will be used to verify that the disks are Keplerian and to measure the masses of the proto-stars and estimate their mass ratios. Finally, even if systems lack a companion, but have a clear disk, their likelihood of later fragmentation will be assessed. In addition to this census, their formation conditions will be characterized and the potential for companion formation will be estimated. The investigators will create a clearer picture of multiplicity at the time of early star formation and how the distribution of multiple stars must change as the stellar systems mature to the main sequence.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.