Planetesimals, Planets, and Debris

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.