High-fidelity Modeling of Rotationally Fissioned Asteroids

Binary asteroids represent an important aspect of the dynamical evolution of small bodies and may provide insight into the evolutionary history of these populations as a whole. Many past studies have focused on Yarkovsky–O’Keefe–Radzievskii–Paddack-driven spinup and disruption as a pathway for binary formation in the inner solar system. While these studies have shown the likelihood that such a process occurred, they are generally limited by assumptions and simplifications in their dynamics models. In this study we apply a high-fidelity and computationally efficient model of binary asteroid dynamics in order to understand the potential effect of higher-order gravity terms and nonplanar dynamics on binary fission. We apply this dynamics model to 66391 Moshup (1999 KW4), 8567 (1996 HW1), and 185851 (2000 DP107) as a representative set of binary and contact binary systems to understand the implications for their fission and formation. Our analysis supports the importance of secondary fission for stable low-mass binary formation as initially suggested by Jacobson and Scheeres. Additionally, we find that the inclusion of higher-fidelity dynamics distorts the dynamical structure of the system, creating a pathway for the secondary to re-collide with the primary. The increased complexity from the inclusion of nonplanar dynamics also suggests more excited spin states of the asteroids during disruptive events such as secondary escape and fission.