# Enhanced interplanetary panspermia in the TRAPPIST-1 system

## TL;DR

This paper models the likelihood of interplanetary panspermia in the TRAPPIST-1 system, suggesting it is significantly more probable than in our Solar System, which could imply higher chances of life origin there.

## Contribution

It introduces a simple probabilistic model for panspermia in TRAPPIST-1 and extends ecological models to estimate transfer rates and potential for life spread.

## Key findings

- Panspermia probability in TRAPPIST-1 is orders of magnitude higher than Earth-Mars.
- Higher transfer rates increase the likelihood of multiple life-bearing planets.
- Observational metrics are proposed to test panspermia hypotheses in TRAPPIST-1.

## Abstract

We present a simple model for estimating the probability of interplanetary panspermia in the recently discovered system of seven planets orbiting the ultracool dwarf star TRAPPIST-1, and find that panspermia is potentially orders of magnitude more likely to occur in the TRAPPIST-1 system compared to the Earth-to-Mars case. As a consequence, we argue that the probability of abiogenesis is enhanced on the TRAPPIST-1 planets compared to the Solar system. By adopting models from theoretical ecology, we show that the number of species transferred and the number of life-bearing planets is also likely to be higher, because of the increased rates of immigration. We propose observational metrics for evaluating whether life was initiated by panspermia on multiple planets in the TRAPPIST-1 system. These results are also applicable to habitable exoplanets and exomoons in other planetary systems.