Contributed Talk - Splinter Exoplanets

Thursday, 14 September 2023, 16:45   (H 3007)

Close stellar flyby and the evolution of Trans-Neptunian Objects: A Gigayear Perspective

Amith Govind, Susanne Pfalzner
Forschungszentrum Jülich

This study examines the evolution of orbital features of trans-Neptunian objects (TNOs) in our Solar System over a Gigayear, subsequent to a close encounter with a star. Our findings suggest this stellar flyby event can account for the observed features of TNOs and Sedna-like objects without affecting the planets' orbits. Over 1 gigayear of evolution, notable orbital transformations occur. A subset of the ‘cold’ TNO population—characterized by low inclination, perihelion distance, and semi-major axis—migrate towards more eccentric orbits with higher semi-major axes, while others with initially high values of these parameters shift towards 'colder' orbits. The extreme TNOs (ETNOs), while experiencing boundary losses, gain new members—primarily particles with eccentricities less than 0.6 and perihelion distances under 40 au—which get scattered into high eccentricity orbits, with some transitions happening over a few million years. Sedna-like objects exhibit minimal population change, with shifts occurring mainly along the boundaries of the population definition in terms of orbital parameters. These findings offer insights into the potential influence of a past stellar encounter on our solar system's architecture.