Comet A117uUD Goes Interstellar after Encountering Saturn in 2022

Abstract

Small solar system bodies may reach hyperbolic orbits after a close interaction with a giant planet. Comet C/1980 E1 (Bowell), with a current value of the eccentricity of 1.057733 ± 0.000008, reached its present-day path after a close encounter with Jupiter in 1980. Comet A117uUD was found by ATLAS South Africa on 2024 June 14. Its current orbit determination, based on 142 observations for a data-arc span of 31 days, places A117uUD among the bodies following hyperbolic orbits (19.51σ, eccentricity of 1.037 ± 0.002). However, it did not come from interstellar space. Here, we show that it reached its current hyperbolic trajectory after a close encounter with Saturn in 2022.