The Space Environment and Atmospheric Joule Heating of the Habitable Zone Exoplanet TOI700-d

TL;DR

This study models the space environment and atmospheric heating of the habitable zone exoplanet TOI700-d, suggesting it may experience relatively mild stellar wind conditions similar to Earth, but uncertainties remain.

Contribution

It provides the first detailed numerical modeling of TOI700-d's space environment using scaled stellar and solar inputs, highlighting potential atmospheric impacts.

Findings

Stellar wind conditions near TOI700-d are comparable to Earth's.

Moderate stellar wind may not threaten atmospheric retention.

Uncertainties in stellar and planetary parameters affect results.

Abstract

We investigate the space environment conditions near the Earth-size planet TOI~700~d using a set of numerical models for the stellar corona and wind, the planetary magnetosphere, and the planetary ionosphere. We drive our simulations using a scaled-down stellar input and a scaled-up solar input in order to obtain two independent solutions. We find that for the particular parameters used in our study, the stellar wind conditions near the planet are not very extreme -- slightly stronger than that near the Earth in terms of the stellar wind ram pressure and the intensity of the interplanetary magnetic field. Thus, the space environment near TOI700-d may not be extremely harmful to the planetary atmosphere, assuming the planet resembles the Earth. Nevertheless, we stress that the stellar input parameters and the actual planetary parameters are unconstrained, and different parameters may result in a much greater effect on the atmosphere of TOI700-d. Finally, we compare our results to solar wind measurements in the solar system and stress that modest stellar wind conditions may not guarantee atmospheric retention of exoplanets.