A new approach to calculating meteoroid heating using atomic-scale simulations

Abstract:

Meteoroids smaller than a microgram are constantly bombarding the Earth, depositing material in the mesosphere and lower thermosphere. Meteoroid ablation, or the explosive disintegration of the meteoroid due to erosive impacts of atmospheric particles, consists of sputtering and thermal ablation. The material lost from meteors is indirectly detected by radars observing electrons released through collisions between ablated atoms and atmospheric molecules. We model the atomic scale interactions that occur during meteoroid ablation using molecular dynamics (MD) simulations. The fraction of energy released from a single atmospheric particle impacting the meteoroid, Λ, was found to be less than 1 and dependent on the characteristics of the meteoroid. Applying this new understanding of energy transfer as a function of the meteoroid state to an ablation model results in a slower temperature increase and mass loss rate as a function of altitude. Notably, this analysis leads to the prediction that meteoroids will generally ablate kilometers lower than previously predicted. This alters the expected electron line densities and visual magnitudes of meteoroids, and affects analysis of radar and visual measurements, including meteoroid mass determination.