Statistical Evidence for Coupled Spin-Orbit Evolution in Asteroid Families

Abstract: Asteroid families, remnants of ancient collisions, offer a unique opportunity to study the long-term effects of non-gravitational forces on small bodies. This study investigates the statistical links between a family's orbital structure and the spin states of its members, seeking observational evidence for coupled spin-orbit evolution driven by the Yarkovsky and YORP effects. Using a comprehensive dataset of 1,464,228 asteroids and focusing on a carefully selected sample of 50 well-characterized families, we calculated family-level metrics to quantify orbital dispersion, spin property distributions, and characteristic member size. Correlation and regression analyses reveal a significant positive correlation between family age and orbital dispersion, consistent with the Yarkovsky effect. Critically, we find a statistically significant relationship between orbital dispersion and the diversity of spin periods within a family, even after accounting for family age and size. This finding provides compelling evidence for coupled spin-orbit evolution, suggesting that YORP-driven spin state changes influence Yarkovsky-driven orbital diffusion. These results provide observational constraints on the complex interplay between non-gravitational forces and the long-term evolution of asteroid populations. \

Subjects:	astro-ph.EP; physics.space-ph
Cite as:	PX:2508.00053