The Galactic potential effects on the Solar System’s minor bodies

Abstract

This project studies the influence of the Milky Way’s galactic gravitational potential on the orbital evolution of distant Solar System minor objects. Using orbital data from Gaia Data Release 3, minor body motion is modeled through the Circular Restricted Three-Body Problem (Sun–Jupiter–minor body), with Galactic perturbations included as an external force. Two Galactic models are considered: the axisymmetric MWPotential2014 and a non-axisymmetric Spiral Arms plus MWPotential2014, both implemented with the galpy library. Numerical integrations are used to analyze secular variations of orbital elements over long timescales. The study focuses on the dwarf planet Eris and a hypothetical Sun-bound asteroid with a semi-major axis of 530 AU. Although galactic forces are much weaker than Solar System forces near the Sun, they produce measurable effects at large heliocentric distances: spiral arm effects are negligible near 100 AU, while both galactic components significantly influence orbital stability beyond 500 AU, with the spiral arm pitch angle playing a key role