Lateral spreading of meteoroids fragments
Popova Olga, Podobnaya Elena
Icarus, In Press, Journal Pre-proof, Available online 1 August 2026
“Highlights
- The lateral size of scattering and/or crater fields on planets with atmospheres is determined by the interaction of fragments after the break up of a meteoroid.
- Estimates of lateral velocity VT differ significantly; fresh crater pairs on Mars provide possibility to study this velocity.
- Conservative estimate of the proportionality coefficient (C ~ 1) in the relation for VT does not contradict to observations, although in some cases, there may be an additional mechanism that increases the repulsive force.
- The dependence of VT on meteoroid density contains the ability to estimate the density of meteoroids based on fragment dispersion. Crater pairs spreading suggests the existence of low-density objects in the total population of meteoroids.”
“The size of meteorite strewn fields and impact crater fields on planets with atmospheres is controlled by both atmospheric sorting and aerodynamic interactions between fragments following meteoroid breakup. These interactions generate lateral velocities perpendicular to the entry trajectory, but published estimates of the resulting fragment separation differ substantially. The dependence of lateral spreading on impactor density and fragmentation conditions suggests that observations of crater-pair separations may provide constraints on meteoroid properties.
In this study, numerical simulations of meteoroid fragmentation and crater-pair formation are compared with 89 fresh Martian crater pairs identified in orbital images. Equal-sized crater pairs are used to evaluate existing estimates of fragment separation, whereas unequal crater pairs provide additional constraints on impactor density and composition. The observed crater separations are broadly consistent with separation coefficients of the order of unity, although some widely separated crater pairs require either larger separation coefficients, unusually oblique impacts, or low-density impactors.
The results demonstrate that fresh Martian crater pairs provide an independent observational constraint on fragment separation during atmospheric entry. The observations are consistent with contributions from impactors of different densities and suggest that low-density objects may represent a component of the present-day Martian impactor population.”
