Cool Dust and Gas in Transitional and Debris Disks

在这个项目中，夏威夷大学的乔纳森·威廉姆斯博士将研究演化后期恒星周围圆盘的直线和连续辐射，因为它们从一个内洞过渡到一个行星形成的碎片系统。星盘是恒星形成过程中不可避免的副产品，也是太阳系外行星的诞生地。行星本身的形成会产生额外的尘埃，这些尘埃可能会在恒星形成并稳定在主序上很久之后才能观察到。圆盘在红外线很容易探测到，但发射的光很厚，不能很好地衡量质量，特别是在外层区域。在亚毫米范围内的观测可以确定磁盘的总质量。尘埃颗粒的大小受能量分布斜率的限制，成像定位受原行星引力比中央恒星辐射影响更大的较大颗粒，线观测揭示了圆盘运动学。该计划将使用詹姆斯·克莱克·麦克斯韦望远镜和亚毫米阵列，位于夏威夷莫纳克亚的亚毫米观测设施。除了这项研究将对我们理解恒星周盘的演化做出贡献外，这项工作还将有助于亚毫米天文学和干涉测量领域的学生的教育和培训。该项目将支持一名研究生的论文研究，一名本科生也将参与该项目，方法是协助观察莫纳克亚火山的运行情况，并整理观察到的圆盘上的辅助数据。该项目及其对行星形成的影响将引起广泛的兴趣，威廉姆斯博士将继续通过夏威夷大学天文研究所的一系列外展讲座在这一领域进行公开演讲。

In this project, Dr. Jonathan Williams (University of Hawaii) will study the line and continuum emission from circumstellar disks in the late stages of evolution, as they transition from an inner hole to a planet-forming debris system. Circumstellar disks are an inevitable by-product of star formation and the birthplaces of extrasolar planets. The formation of planets themselves generates additional dust that may be observed long after the star has formed and has settled onto the main sequence. Disks are readily detectable in the infrared but the emission is optically thick and is a poor measure of the mass, especially in the outer regions. Observations in the submillimeter regime allow total disk masses to be determined. Dust grain sizes are constrained from the slope of the energy distribution, imaging locates the larger particles that are influenced more by the gravity of a protoplanet than the radiation from the central star, and line observations reveal the disk kinematics. The program will be carried out using the James Clerk Maxwell Telescope and the Submillimeter Array, submillimeter observing facilities on Mauna Kea, Hawaii. In addition to the contribution this research will make in our understanding of the evolution of circumstellar disks, this work will also contribute to the education and training of students in areas of submillimeter astronomy and interferometry. The project will support the dissertation research of a graduate student and an undergraduate student will also participate in the project by assisting in observing runs on Mauna Kea and collating ancillary data on the observed disks. This project, with its implications for planet formation, will be of broad interest and the Dr. Williams will continue to give public talks in this field through an established outreach lecture series at the University of Hawaii's Institute for Astronomy.