Frequency of Coronal Mass Ejection Impacts with Early Terrestrial Planets and Exoplanets Around Active Solar-like Stars

TL;DR

This study models how magnetic fields of young Sun-like stars influence coronal mass ejection trajectories, significantly increasing impact frequency estimates on early planets and exoplanets, affecting atmospheric and prebiotic chemistry.

Contribution

It introduces a model showing CME deflections toward the ecliptic plane, increasing impact frequency estimates on early planets and exoplanets around active stars.

Findings

CME deflections are directed toward the astrospheric current sheet.

Impact frequency of CMEs on early planets is increased to ~30%.

Implications for atmospheric evolution and prebiotic chemistry are significant.

Abstract

Energetic flares and associated coronal mass ejections (CMEs) from young magnetically active solar-like stars can play a critical role in setting conditions for atmospheric escape as well aspenetration of accelerated particles into their atmospheres that promotes formation of biologically relevant molecules. We have used the observationally reconstructed magnetic field of the 0.7 Gyr-young Suns twin, k1 Ceti, to study the effects of CME deflections in the magnetic corona of the young Sun and their effects on the impact frequency on the early Venus, Earth and Mars. We find that the coronal magnetic field deflects the CMEs toward the astrospheric current sheet (ACS). This effect suggests that CMEs tend to propagate within a small cone about the ecliptic plane increasing the impact frequency of CMEs with planetary magnetospheres near this plane to ~ 30 percent or by a factor of 6 as compared to previous estimate by Airapetian et al. 2016. Our model has important implications for the rise of prebiotic chemistry on early terrestrial planets as well as terrestrial type exoplanets around young G-K dwarfs.