The Influence of Space Environment on the Evolution of Mercury

TL;DR

This paper estimates how Mercury's extreme space environment, especially solar wind and radiation, has contributed to surface material loss over billions of years, influencing its geological evolution.

Contribution

It provides a rough estimation of Mercury's surface material loss rate over time, highlighting the combined effects of ion sputtering, photon stimulated desorption, and diffusion in early planetary erosion.

Findings

Potential surface layer loss of up to 20 meters.

Significant sodium depletion due to erosion processes.

Early extreme conditions enhanced material removal.

Abstract

Mercury, due to its close location to the Sun, is surrounded by an environment whose conditions may be considered as "extreme" in the entire Solar System. Both solar wind and radiation are stronger with respect to other Solar System bodies, so that their interactions with the planet cause high emission of material from its surface. Moreover, the meteoritic precipitation plays a significant role in surface emission processes. This emitted material is partially lost in space. Although under the present conditions the surface particles loss rate does not seem to be able to produce significant erosion of the planetary mass and volume, the long-term effects over billions of years should be carefully considered to properly understand the evolution of the planet. In the early stages, under even more extreme conditions, some of these processes were much more effective in removing material from the planet's surface. This study attempts to provide a rough estimation of the material loss rate as a function of time, in order to evaluate whether and how this environmental effect can be applied to understand the Hermean surface evolution. We show that the most potentially effective Sun-induced erosion process in early times is a combination of ion sputtering, photon stimulated desorption and enhanced diffusion, which could have caused the loss of a surface layer down to a depth of 20 m, as well as a relevant Na depletion.