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

虽然最近的调查表明行星的形成是普遍的，但在年轻的双星系统中，尤其是在紧密的双星系统中，很少发现为行星形成提供原料的星周盘。考虑到1/3到1/2的恒星出现在双星系统中，自然会产生这样的问题：这些系统中的可变辐射和引力场如何影响星周盘和其中形成的行星的性质（和生存能力）。这项研究计划将使用覆盖宽波长范围的数据来推进我们对近距离和广泛分离的双星样本的星周盘结构和演化的理解。该项目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。首席研究员提议对年轻的双星进行大范围的研究（从几到几百个天文单位），以表征(1)多星系成员对星周盘形成、结构和进化的影响，以及(2)为什么在一些宽的双星系统中，尽管人们可能预期伴星的动力学影响是无关重要的，但星周盘的演化却显得不均匀。较宽的对将为更细致地研究星周盘的一般行为提供基础，而较近的对将不仅提供对盘的洞察，还提供对双星形成模型的洞察。为了实现这些目标，PI将采用高分辨率红外光谱，高角度分辨率光学/红外成像，时间序列光度测定-包括地面和美国宇航局的K2 -来确定旋转周期，以及通过ALMA通过亚毫米尘埃发射对星周盘进行直接成像。对这些数据的分析将导致对近距离和宽距离双星中星周盘的形成和演化的全面了解，并将其视为恒星和双星特性的函数。此外，通过结合单个旋转周期和投影旋转的值，最终可能测量双星的恒星倾角。偏离的恒星旋转轴可能为盘演化背后的动力学过程提供线索。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。

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.