Main Belt Asteroid Histories: Simulations of erosion, cratering, catastrophic dispersions, spins, binaries and tumblers

TL;DR

This paper presents a comprehensive simulation framework for the collisional and dynamical history of main belt asteroids, offering new insights into their spin states, shapes, and dispersal processes, while highlighting gaps in current understanding.

Contribution

The paper introduces the SSAH simulation code and models that enhance understanding of asteroid evolution, including spin distributions and disruption processes, with implications for interpreting asteroid observations.

Findings

Distribution of asteroid spins and shapes explained by simulations

Irrelevance of traditional strength spin limits for large asteroids

Identification of gaps in current asteroid evolution knowledge

Abstract

This is a study of the history of the asteroids in the main asteroid belt. Collisions have been the dominant process. Every asteroid has been impacted by others a multitude of times, with consequences of cratering, erosion, spin increments, fragmentation, and occasional catastrophic disruption and dispersion. Extensive information for asteroid orbits, sizes, shapes, composition, and rotation rates of those asteroids is now available. Those are a result of their history, but to interpret them requires understanding the processes. That understanding can be improved by simulations of the history. A simulation needs robust models of the dynamical and collisional events. Such models have evolved substantially in the last few decades. Here I present current models, a method, and a code "SSAH" for stochastic simulations of the history of the main belt. That code gives a framework upon which existing and future models can be based. The results lead to new paradigms for asteroid histories including the distribution of spins; the irrelevance of strength spin limits; the "unusual" spins of 2001 OE84; and of large slow-spinning tumbling objects (Mathilde); the "V-shape" in the spin versus diameter plot; the non-Maxwellian distribution of spins of a given diameter range; the numbers of expected tumblers, and more. At the same time, the simulations expose gaps in our knowledge that require further research. The SSAH code is freely available for the use of others.