The architectures of planetary systems discovered by Kepler are poorly understood. There
are far more single-transiting planets than expected from the analysis of the number of
multi-transiting systems, assuming that all planetary systems are co-planar. However, stars
are not born in isolation, and interactions between stars can perturb their planetary
systems.
This project uses N-body simulations to investigate the dynamical evolution of
different young planetary systems containing close-in Super-Earths that are subjected to
stellar fly-bys at different distances. The fly-bys are set up to mirror those occurring in young
star-forming regions. We have run a large set of long-term planetary integrations to show
that planetary architectures can be significantly modified after only a single fly-by
event. The example in the plot shows the evolution of the mutual inclination between two
Super-Earths in two different simulations, each covering a period of 100 Myr. These
simulations differ in the initial separation between the planets. The same close fly-by
(occurring at 10 kyr) can either result in a considerable difference in the mutual inclination
of up to ~6 degrees (for an initial separation of 10 mutual Hill radii) or when initially placed
further apart (14 mutual Hill radii) of less than 0.1 degrees.
