Dynamical Evolution of Planetary Systems in Star Clusters

Thousands of exoplanets, including multiple systems, have been identified in recent years. The formation of planetary systems from protoplanetary disks and planetary embryos has been well studied, in particular how the observed diversity of planetary systems is generated by processes such as planet-planet scattering, secular evolution, and interaction between planets and gas/debris disks. Almost all of this work has focused on the formation and evolution of isolated planetary systems. The birth places of many if not all stars, however, is in a star cluster or association, which may either disperse after some time or remain an open cluster. In this project we will continue to study how planetary systems are shaped and reorganized by the external dynamical effects in their nascent star cluster by encounters with other stars.

In this project period we will focus on the delayed destabilization of planetary systems after gravitational encounters with other stars, and on the influence of binary stars, which are frequent in star clusters. In this context the host star of a planetary system can be a binary star (hosting so-called S- and R-planets) as well as the passing object of the gravitational encounter. Furthermore it has been found that mutual inclinations of planetary orbits are a consequence of gravitational encounters in star clusters; this will be subject of a detailed study; observation of extrasolar planets gives yet very little information on this. The project consists of theoretical numerical models of the coupled evolution of planetary systems, in close connection with an evolving dynamial model of a surrounding star cluster.