From cradle to grave: Environment as the origin of diversity in exoplanetary systems

Andrew Winter, Institut für Theoretische Astrophysik, Heidelberg — November 29, 2021

Despite the discovery of thousands of exoplanetary systems, the origin of the observed diversity of these systems remains one of the biggest open questions in planetary science. However, models for the formation of these planetary systems frequently consider only an isolated-star disc system. In this talk, I discuss how the broader environment of the (proto)planetary system is a necessary ingredient in understanding the observed population of exoplanets. To this end I will review evidence of that the environment sculpts these systems 'from cradle to the grave'. In the 'cradle', I show that external UV fields from young stars frequently irradiate the discs of dust and gas from which planets form, shortening the lifetime and reducing the available mass budget. For the oldest stars occupying globular clusters, I present an analytic approach to quantifying how planets evolve as a result of dynamical encounters. This evolution frequently leads to the 'grave' of these planets due to tidal disruption. This process may explain the lack of hot Jupiters detected by transit surveys of globular clusters. I conclude by discussing how future studies may help to unravel the many remaining problems in understanding the origins of exoplanets.