Minimal Energy Transfer of Solid Material Between Planetary Systems

TL;DR

This paper investigates a low-energy dynamical mechanism for transferring solid material between planetary systems, potentially increasing the likelihood of interstellar lithopanspermia, though biological viability remains uncertain.

Contribution

It introduces a chaotic dynamical process involving nearly parabolic trajectories that enables minimal energy transfer between stellar systems, enhancing transfer probability.

Findings

Low velocity transfer mechanisms are more efficient than hyperbolic trajectories.

Significant material transfer could have occurred from the early Solar System to nearby stars.

Transfer probability depends on stellar mass and cluster size.

Abstract

The exchange of meteorites among the terrestrial planets of our Solar System is a well established phenomenon that has triggered discussion of lithopanspermia within the Solar System. Similarly, could solid material be transferred across planetary systems? To address this question, we explore the dynamics of the transfer of small bodies between planetary systems. In particular, we examine a dynamical process that yields very low escape velocities using nearly parabolic trajectories, and the reverse process that allows for low velocity capture. These processes are chaotic and provide a mechanism for minimal energy transfer that yield an increased transfer probability compared to that of previously studied mechanisms that have invoked hyperbolic trajectories. We estimate the transfer probability in a stellar cluster as a function of stellar mass and cluster size. We find that significant amounts of solid material could potentially have been transferred from the early Solar System to our nearest neighbor stars. While this low velocity mechanism improves the odds for interstellar lithopanspermia, the exchange of biologically active materials across stellar systems depends greatly upon the highly uncertain viability of organisms over the timescales for transfer, typically millions of years.