Planetesimals, Planets, and Debris

我建议进行行星天体物理学方面的研究，这将有助于我们理解太阳系是如何形成和演化的。这项研究将首先关注行星(行星体)的组成部分是如何发展的，其次是研究产生的系统是如何随着时间的推移而演变的。这项研究的机构自然而然地被选为剑桥大学应用数学和理论物理系，在那里，天体物理学小组有一个新的重点，由John Papaloizou教授和Gordon Ogilvie博士领导的行星形成、盘动力学和行星环。这项研究特别及时，因为在过去几年中，探测行星和原行星系统的观测能力显著增强，并开始为行星形成模型提供严格的限制。与此同时，计算机集群已经变得快速、相当便宜、易于管理，并且可以处理有趣的大型问题。最后，理论模型已经发展到可以用数值模拟进行详细测试，并将结果直接与观测结果进行比较的地步。这项拟议的工作将包括直接的数值模拟，目的是描述行星体是如何形成的，并对决定恒星周围圆盘最终状态的参数施加定量限制。我将首先通过一系列直接的数值模拟来测试小行星形成的模型。这些模拟将解决并有可能解决行星形成过程中长期存在的尘埃增长问题。小行星的形成很难通过观测来研究，因为这些物体太大了，无法在尘埃盘调查中探测到，也太小了，无法通过它们自己的发射来探测到。此外，数值模型和计算技术还不够强大，无法直接解决这个问题。我提供了一种方法，该方法利用允许创建尘埃聚集体的高效且通用的数字代码。然后，可以将结果与对年轻恒星周围尘埃盘的观测进行比较。此外，我建议研究行星系统是如何形成的，以及为什么一些成熟的恒星似乎有碎片盘。我在这里提出的圆盘演化工作将能够确定在成熟恒星周围观察到的碎片圆盘是柯伊伯带状物体(对我们太阳系中的尘埃做出贡献)研磨的结果，还是不同的演化阶段。我建议在剑桥大学DAMTP的天体物理学小组进行这项工作，因为他们在行星形成和圆盘动力学的研究方面拥有相当多的专业知识。

I propose to conduct research in planetary astrophysics that will contribute to our understanding of how solar systems formed and evolved. This research will first focus on how the building blocks of planets (planetesimals) develop and second on how the resulting system evolves over time. The natural choice of institution for this research is the Department of Applied Mathematics and Theoretical Physics, University of Cambridge, where the Astrophysics Group has a new emphasis on planet formation, disk dynamics, and planetary rings led by Prof. John Papaloizou and Dr. Gordon Ogilvie. The research is particularly timely because observational capabilities to detect both planetary and protoplanetary systems have grown significantly in the past few years, and are beginning to provide stringent constraints for models of planet formation. At the same time computer clusters have become fast, reasonably cheap, and easy to manage and can handle interestingly large problems. Finally, theoretical models have advanced to the point were they can be tested in detail with numerical simulations and the results directly compared to observations. The proposed work will consist of direct numerical simulations with a goal to characterize how planetesimals form and to put quantitative constraints on the parameters that determine the final state of the circumstellar disks. I will begin by testing models of planetesimal formation through a series of direct numerical simulations. These simulations will address and potentially solve the long-standing problem of dust growth in planet formation. Planetesimal formation is difficult to study observationally because the objects are too large to detect in dust disk surveys and too small to be detected through their own emission. In addition, numerical models and computational techniques have simply not been powerful enough to address the problem directly. I provide a method that utilizes an efficient and versatile numerical code that allows the creation of dust aggregates. The results can then be compared with observations of dusty disks around young stars. In addition, I propose to study how planetary systems form and why some mature stars seem to have disks of debris. The disk evolution work that I propose here will be able to determine if the debris disks that are observed around mature stars are the result of the grinding of Kuiper Belt-like objects (which contribute to the dust in our solar system) or a different phase of evolution. I propose to conduct this work in the Astrophysics Group at DAMTP, Cambridge University because of their considerable expertise in the study of planet formation and disk dynamics.