From disks to planets: end-to-end modelling of the planet formation process

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Human beings have long been occupied with the question of how planetary systems form and evolve. The answer is central to placing ourselves in context within the Universe, to the search for other habitable worlds, and ultimately, to the search for other life. Though more than 250 planets have been detected around other stars over the past decade, our knowledge of how both they and our own Solar System came to be is still very incomplete. Using a new hybrid computer code developed by the principal investigator, it is for the first time possible to perform an end-to-end simulation of the entire formation process---in essence, of how a disk around a young star converts itself into planets. This code combines the speed of an ``N-body" scheme optimized for planetary systems (based on the existing SyMBA package) with a one-dimensional implementation of a protostellar disk (which represents the disk as made up of nested rings). These two parts are coupled using standard prescriptions for (i) the dynamical interaction of a planet with a disk, and (ii) the rate at which a planet grows its atmosphere by gravitationally pulling in gas from the disk. With this computer code as the primary tool, the research proposed here is aimed at advancing our understanding of planet formation. A series of key additions and enhancements will be made to the code over time, each allowing a new aspect of the planet formation process to be studied. At the same time, the high speed of the code---several days to simulate the several-million-year lifespan of a protostellar gas disk---will be maintained. It is intended that three summer students, three graduate students and one postdoctoral researcher will be trained/employed over the course of the project. At the end of the funding period, the finished, fully documented and rigorously tested code will be made freely available to the public.