Implications of Captured Interstellar Objects for Panspermia and Extraterrestrial Life

TL;DR

This paper models the capture of interstellar objects by planetary systems, estimating sizes and implications for panspermia, and discusses how captured objects could transfer life and be distinguished observationally.

Contribution

It introduces a gravitational capture model for interstellar objects in specific systems and explores their potential role in transferring life.

Findings

Largest captured objects are tens of km in radius around Sun-Jupiter and Earth-sized in Alpha Centauri.

Captured interstellar comets can be distinguished by their orbital trajectories and isotope ratios.

Implications for panspermia through rocky material transfer are discussed.

Abstract

We estimate the capture rate of interstellar objects by means of three-body gravitational interactions. We apply this model to the Sun-Jupiter system and the Alpha Centauri A\&B binary system, and find that the radius of the largest captured object is a few tens of km and Earth-sized respectively. We explore the implications of our model for the transfer of life by means of rocky material. The interstellar comets captured by the "fishing net" of the Solar system can be potentially distinguished by their differing orbital trajectories and ratios of oxygen isotopes through high-resolution spectroscopy of water vapor in their tails.