On the rotational properties of M-type asteroids: recent evidence for higher rotation rates

TL;DR

This study provides evidence that M-type asteroids tend to have higher rotation rates than other asteroid types, suggesting greater internal cohesion related to their metallic composition.

Contribution

It introduces a multi-method statistical approach to robustly demonstrate the link between metallic composition and faster asteroid rotation rates.

Findings

Metallic asteroids rotate faster on average

Results are consistent across different statistical methods

Findings support higher internal cohesion in M-type asteroids

Abstract

Rotational dynamics of asteroids carry important information about their internal structure, collisional history and material composition. This work investigates whether metallic (M-type) asteroids exhibit systematically higher rotation rates than the broader asteroid population. Using recent Mahlke's taxonomy and a multi-method statistical approach that combines classical hypothesis testing, regression modeling, and resampling techniques, we consistently find evidence that metallic asteroids rotate, on average, faster. The results remain robust across different ways of controlling for asteroid size and sampling biases. While limitations remain due to sample size, heterogeneous data sources, and possible selection effects, the convergence of independent methods strengthens the conclusion that metallic composition is associated with higher rotation rates. This finding supports the hypothesis that metallic bodies possess greater internal cohesion, with implications for the formation and collisional evolution of small bodies in the Solar System.