Atmospheric chemical evolution driven by meteoritic interactions

Planetary atmospheres - and their potential habitability - evolve under external energy inputs, including stellar irradiation, cosmic rays, and meteoroid accretion. Meteoroid entry is ubiquitous across planetary systems but its role as a driver of atmospheric chemical evolution remains relatively underexplored. Meteorites readily acquire high entry velocities through planetary gravitational focusing, generating strong shock waves in planetary atmospheres during the entry process. The resulting shock heating drives non-equilibrium chemical reactions that can alter atmospheric compositions. We investigate these processes using coupled aerodynamical and chemical kinetic simulations of meteoroid entry. Our results demonstrate that meteoritic heating can significantly contribute to the production of organic species. Compared with other external energy sources such as stellar irradiation and cosmic rays, meteoroid entry processes have received relatively limited attention in atmospheric chemistry studies. Our results suggest that unlike stellar irradiation, which is primarily absorbed in the upper atmosphere, meteoroids can directly deposit energy into deeper atmospheric layers where most of the atmospheric mass resides. This enables shock-induced chemistry to proceed efficiently in dense atmospheric regions. Therefore, meteoritic heating may be a major contributor to chemical production in planetary atmospheres.

Speaker: Ryushi Miyayama, Stanford University

Room 350/372