Asteroid Fragmentation Approaches for Modeling Atmospheric Energy Deposition
Paul J. Register, Donovan L. Mathias, Lorien F. Wheeler
In Press, Accepted Manuscript, Available online 18 November 2016
• Fragmentation modeling approaches are compared using Chelyabinsk meteor data.
• A new model combining discrete and cloud-like fragmentation methods is presented.
• Combining discrete and cloud-like fragmentation better models observed features.
• Cloud-like breakup characteristics are needed to represent large airburst flares.
• Discrete fragmentation methods are needed reproduce multiple flares.”
“During asteroid entry, energy is deposited in the atmosphere through thermal ablation and momentum-loss due to aerodynamic drag. Analytic models of asteroid entry and breakup physics are used to compute the energy deposition, which can then be compared against measured light curves and used to estimate ground damage due to airburst events. This work assesses and compares energy deposition results from four existing approaches to asteroid breakup modeling, and presents a new model that combines key elements of those approaches. The existing approaches considered include a liquid drop or “pancake” model where the object is treated as a single deforming body, and a set of discrete fragment models where the object breaks progressively into individual fragments. The new model incorporates both independent fragments and aggregate debris clouds to represent a broader range of fragmentation behaviors and reproduce more detailed light curve features. All five models are used to estimate the energy deposition rate versus altitude for the Chelyabinsk meteor impact, and results are compared with an observationally derived energy deposition curve. Comparisons show that four of the five approaches are able to match the overall observed energy deposition profile, but the features of the combined model are needed to better replicate both the primary and secondary peaks of the Chelyabinsk curve.”