Circumstellar Disk Evolution and Implications for Planet Formation in the Binary Environment

虽然最近的调查表明行星形成是普遍存在的，但在年轻的双星系统中，尤其是在近距离双星系统中，为行星形成提供原材料的星盘较少被检测到。鉴于1/3到1/2的恒星出现在双星系统中，自然就会产生这样的问题：这些系统中可变的辐射和引力场如何影响星盘和形成在其中的行星的性质(和生存能力)。这项研究计划将使用覆盖宽波长范围的数据，以促进我们对近距离和远距离双星样本的环绕恒星盘的结构和演化的理解。这项计划将支持一名博士后研究人员以及几项广泛的努力，以激发历史上代表性不足的社区对物理科学的兴趣。主要研究人员提议对大范围的分离(从几个到几百个A.U)的年轻双星进行研究。为了表征(1)多系统中的成员对星盘的形成、结构和演化的影响，以及(2)为什么在一些宽广的双星系统中，尽管人们可能认为伴星的动力学效应是无关紧要的，但星盘的演化似乎是不均匀的。较宽的双星对将为更细微的研究恒星周盘行为提供基础，而较近的双星对的圆盘特征将不仅提供对盘的洞察，还将提供双星形成模型的洞察。为了实现这些目标，PI将使用高分辨率红外光谱、高角分辨率光学/红外成像、时间序列光度测量--既包括地面测量，也包括NASA的K2测量--以确定自转周期，以及通过ALMA发射的亚毫米尘埃对恒星周盘进行直接成像。对这些数据的分析将导致对紧密双星和宽大双星中的恒星周盘的形成和演化的全面图景，认为这是它们的恒星和双星性质的函数。此外，通过结合单独的自转周期和投影自转的值，最终有可能以双星来测量恒星的倾斜度。

While recent surveys suggest that planet formation is universal, circumstellar disks, which provide the raw material for planet formation, are detected less often in young binary star systems, particularly in close binaries. Given that 1/3 to 1/2 of all stars occur in binary systems, the question naturally arises as to how the variable irradiation and gravitational fields in these systems influence the properties (and survivability) of circumstellar disks and the planets that form therein. This research program will use data covering a wide wavelength range to advance our understanding of the structure and evolution of circum-stellar disks for a sample of both close and widely separated binaries. This program will support a post-doctoral researcher as well as several broad efforts to stimulate interest in the physical sciences among historically underrepresented communities.The principal investigator proposes a study of young binary stars over a wide range of separations (from a few to several hundred A.U.) to characterize (1) the impact membership in a multiple system has on circumstellar disk formation, structure, and evolution, and (2) why circumstellar disk evolution appears uneven in some wide binary systems despite what one might have expected to be inconsequential dynamical effects of the companion star. Wider pairs will provide the basis of a more nuanced study of circumstellar disk behavior in general, while disk characteristics in closer pairs will offer insight into not only disk but also binary formation models. To carry out these goals, the PI will employ high-resolution infrared spectroscopy, high-angular resolution optical/infrared imaging, time series photometry - both ground-based and with NASA’s K2 - to determine rotation periods, as well as direct imaging of circumstellar disks through their sub-millimeter dust emission with ALMA. The analysis of these data will lead to a comprehensive picture of both the formation and evolution of circumstellar disks in close and wide binaries viewed as a function of their stellar and binary properties. Additionally, by combining individual rotation periods and values for the projected rotation it may ultimately be possible to measure the stellar inclination in binaries. Misaligned stellar rotation axes may provide clues to dynamical processes behind disk evolution.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.