Formation of sharp edges and planar areas of asteroids by polyhedral abrasion

TL;DR

This paper introduces an abrasion model explaining how asteroid shapes evolve through micro-collisions, leading to sharp edges and flat areas, aligning with observed features and emphasizing the importance of fallback ejecta.

Contribution

The paper presents a novel averaged abrasion model based on micro-collisions that predicts diverse asteroid shape evolution paths, including flat areas and edges, differing from traditional spheroid outcomes.

Findings

Model reproduces observed flat areas and edges on asteroids

Collision fallback rate influences shape evolution pathways

Model aligns with photometry-derived asteroid features

Abstract

While the number of asteroids with known shapes has drastically increased over the past few years, little is known on the the time-evolution of shapes and the underlying physical processes. Here we propose an averaged abrasion model based on micro-collisons, accounting for asteroids not necessarily evolving toward regular spheroids, rather (depending on the fall-back rate of ejecta) following an alternative path, thus confirming photometry-derived features, e.g. existence of large, relatively flat areas separated by edges. We show that our model is realistic, since the bulk of the collisions falls into this category.