The Interplanetary Habitable Zone

TL;DR

This paper introduces a measure for assessing the potential for sustaining life across interplanetary systems, using models to compare habitability in our solar system and exoplanetary systems like Trappist-1.

Contribution

It develops a multi-modal figure of merit and agent-based models to evaluate and compare interplanetary habitability across different planetary systems.

Findings

Solar system shows higher habitability potential than Trappist-1.

Resource distribution influences migration and habitability patterns.

Sensitivity analysis highlights key factors affecting interplanetary habitability.

Abstract

The concept of a system-wide measure of the sustainment of life (habitability) for space-faring interplanetary species is introduced and explored. Although largely agnostic to the details of how interplanetary life might operate (e.g., via technology or by utilizing organism traits that are, as of now, unknown to us), some assumptions must be made about energy harvesting, orbital mobility costs, radiation risks, and resource requirements. A multi-modal figure of merit is developed for evaluating an interplanetary habitable zone (IHZ). An agent-based model is also developed to simulate the dispersal of interplanetary life in a planetary system and characterize the IHZ. For the solar system, resource weightings between planetary bodies dictate many overall behaviors, including the sequence of migration from Earth to the Moon, Mars, and asteroid belt. Comparisons with the Trappist-1 exoplanetary system also point to critical sensitivities in the balance between resource availability and risk or cost factors (e.g., radiation risks and orbital Delta-v costs) that determine the structure of an IHZ. Results suggest that our solar system may have an inherent, and significant, advantage for a space-faring species over a system like Trappist-1. This modeling approach may also have application to emerging space economies in our own solar system.