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“Effects of Young Star Clusters on their Constituent Solar Systems(and the Discovery of a Robust Orbit Instability)” Dr. Fred Adams University of Michigan |
| Most stars -- and hence most solar systems -- form within groups and clusters. This talk explores how these star forming environments affect the solar systems forming within them. The discussion starts with the dynamical evolution of young clusters with N = 100 - 1000 members. We use N-body simulations to study how evolution depends on system size and the initial conditions. 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 and distributions of radial locations. These results then provide a framework from which to assess the effects of clusters on solar system formation. The distributions of radial positions are used in conjunction with FUV luminosity distributions to determine the radiation exposure of circumstellar disks. Photoevaporation calculations then determine the efficacy of radiation in removing gas from the systems (resulting in loss of planet forming potential). 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. The main result of this work is a quantitative determination of the effects of clusters on forming solar systems. Along the way, we set interesting constraints on the possible birth environments for our own solar system. Finally, through the study of orbits in these extended mass distributions, we have discovered a robust orbit instability that operates whenever the potential is sufficiently triaxial. This orbit instability not only affects the dynamics of forming star clusters, but also arises in the dynamics of dark matter halos. |