Physical trigger of meteoroid fragmentation onset at Mars

Determine whether fragmentation onset in millimetre-sized meteoroids entering the Martian atmosphere is triggered primarily by atmospheric mechanical forces, such as dynamic pressure, or by thermal degradation associated with accumulated aerodynamic heating.

Background

The study projects physical meteoroid properties inferred from 144 Earth-based meteor observations into the Martian atmosphere using an erosion–fragmentation model. Unlike the single-body ablation model, the erosion–fragmentation model requires a condition specifying when erosion and fragmentation begin. Because the atmospheric environment and entry velocities differ substantially between Earth and Mars, the terrestrial erosion-onset height cannot be transferred directly.

The authors identify the physical mechanism initiating fragmentation as unresolved and evaluate three phenomenological mappings: a constant atmospheric-density trigger, a constant dynamic-pressure trigger representing mechanical detachment, and a constant accumulated-heat trigger representing thermal degradation of a binding material. Martian optical meteor observations could help distinguish among these competing mechanisms.