Dr. Fred Adams
University of Michigan

University of Florida Astronomy Colloquium - Apr 12th, 2006

The Effects of Groups/Clusters on Nascent Solar Systems

Most stars -- and hence most solar systems -- form within groups or clusters. This talk discusses how these star forming environments can affect the planetary systems forming within them. The discussion starts with the dynamical evolution of young stellar clusters with N = 100 - 1000 members. We use N-body simulations to explore how evolution depends on system size N and the initial conditions. Motivated by recent observations of extremely young systems, this study compares subvirial and virial starting states. Multiple realizations of equivalent cases (100 simulations per case) are used to build up a robust statistical description of these systems, e.g., distributions of closest approaches, mass profiles, and distributions of radial locations. These results provide a framework from which to assess the effects of these clusters on star and planet formation. The distributions of radial positions are used in conjunction with distributions of FUV luminosities to determine the radiation exposure of circumstellar disks. Photoevaporation calculations then determine the efficacy of radiation in removing gas from the systems. The distributions of closest approaches are used in conjunction with scattering cross sections (calculated from 100,000 numerical experiments) to determine the probability of solar system disruption. Finally, we use the nearby cluster NGC 1333 as a test case. Our main conclusion is that clusters in this size range have a modest effect on forming planetary systems. Further, this work seeks to describe these effects specifically and quantitatively.