Small Solar System bodies well beyond Neptune – from Trans-Neptunian Objects (TNOs) up to the Oort cloud objects – lie at the interface of the Sun’s sphere of influence and its interstellar environment. Their dynamics is shaped by the gravitational influence of both our Solar System and the stellar and galactic environment in which it evolved over time. Besides, being the most pristine objects, they are tracers of the formation and the dynamical evolution of the outermost part of the Solar System. Indeed, their dynamics is structured by these complex mix of interactions from the inside by the giant planets and on the outside by stellar encounters, and the galactic potential along the orbital evolution of the whole Solar System in the Milky Way.
We aim to understand how planetary and stellar interactions have shaped the Outermost Solar System since its formation some 4.5 Gyr ago. Our approach is based on combining the knowledge gained by observational advances on the populations of TNOs and comets (mostly from recent surveys and the soon-to-start Rubin/LSST), together with a state-of-art knowledge and modelling of the local stellar and galactic environment (much of which has come from the Gaia mission). We will develop dedicated numerical N-body simulations, taking into account all relevant gravitational interactions, and comparing the outputs to observed orbital distributions of these small bodies. By bringing together world-experts on galactic dynamics, stellar populations, Solar System dynamics and observations, we provide the ideal conditions to achieve a deeperunderstanding of the environment in which the Solar System has evolved, and test models for the formation of the Oort cloud.
By using computational tools and observational datasets, there are several general questions we will address in this collaborative work: