# Stellar Influence on Heavy Ion Escape from Unmagnetized Exoplanets

## TL;DR

This study uses a hybrid plasma model to analyze how stellar wind conditions influence heavy ion escape from unmagnetized exoplanets, highlighting significant variability and potential limits in ion loss rates under different stellar environments.

## Contribution

It provides a systematic analysis of plasma environment effects on ion escape for habitable exoplanets around M-dwarfs, extending understanding beyond solar system conditions.

## Key findings

- Ion loss rates vary significantly with stellar wind conditions.
- Increased stellar wind pressure can limit ion loss due to diffusion or production constraints.
- Extrapolating solar system ion loss processes to extreme environments requires caution.

## Abstract

Planetary habitability is in part determined by the atmospheric evolution of a planet; one key component of such evolution is escape of heavy ions to space. Ion loss processes are sensitive to the plasma environment of the planet, dictated by the stellar wind and stellar radiation. These conditions are likely to vary from what we observe in our own solar system when considering a planet in the habitable zone around an M-dwarf. Here we use a hybrid global plasma model to perform a systematic study of the changing plasma environment and ion escape as a function of stellar input conditions, which are designed to mimic those of potentially habitable planets orbiting M-dwarfs. We begin with a nominal case of a solar wind experienced at Mars today, and incrementally modify the interplanetary magnetic field orientation and strength, dynamic pressure, and Extreme Ultraviolet input. We find that both ion loss morphology and overall rates vary significantly, and in cases where the stellar wind pressure was increased, the ion loss began to be diffusion or production limited with roughly half of all produced ions being lost. This limit implies that extreme care must be taken when extrapolating loss processes observed in the solar system to extreme environments.