The effect of encounters with interstellar objects of planetary and substellar masses on the Solar system dynamics

We explore the immediate and long-term consequences of close passages of interstellar planet-mass and substellar-mass objects for the Solar system dynamics. Two approach orbits of such objects are considered, namely, the hyperbolic orbits of two real interstellar objects, 1I/'Oumuamua and 2I/Borisov. For each orbit, a series of massive numerical experiments is performed, in which the mass of the interstellar object is varied in small steps over a broad range. It is shown that even if the interloper does not experience any close encounter with a planet of the Solar system, and has a mass typical for a free-floating planet, a disruption of the Solar system may occur on time scales of several million years.