Exploring rotational properties and the YORP effect in asteroid families

This thesis investigates the long-term dynamical evolution of asteroid families by analyzing the rotational properties of 7,478 asteroids with spin period measurements and 3,365 with obliquity determinations across 28 families ranging from 14 Myrs to 3 Gyrs in age. By introducing a dimensionless timescale normalized by the classical YORP timescale, I compared rotational states across different evolutionary stages. The analysis reveals that the fraction of slow rotators increases steeply, saturating at $f_{slow} \simeq 0.25$ around a normalized time breakpoint of $t_{bp} \simeq 20$. This suggests a stochastic YORP timescale approximately 10 times longer than the classical prediction. Furthermore, the polarization fraction reaches a peak of $\simeq 0.8$ at $t \simeq 16$ before decaying toward the random limit of 0.5 for $t \ge 20$, indicating the eventual dominance of collisional spin reorientation. These findings were applied to a hierarchical Bayesian model to disentangle the overlapping Polana and Eulalia families, providing probabilistic membership assignments. Additionally, this work demonstrates that rotational properties can serve as a critical new dimension for age estimation in the upcoming LSST era.