Dynamical Evolution of the Didymos-Dimorphos Binary Asteroid as Rubble Piles following the DART Impact

Abstract

Previous efforts have modeled the Didymos system as two irregularly shaped rigid bodies, although it is likely that one or both components are in fact rubble piles. Here, we relax the rigid-body assumption to quantify how this affects the spin and orbital dynamics of the system following the DART impact. Given known fundamental differences between our simulation codes, we find that faster rigid-body simulations produce nearly the same result as rubble-pile models in scenarios with a moderate value for the momentum enhancement factor, $\beta$ ($\beta \sim 3$) and an ellipsoidal secondary. This indicates that the rigid-body approach is likely adequate for propagating the post-impact dynamics necessary to meet DART Mission requirements. Although, if Dimorphos has a highly-irregular shape or structure, or if $\beta$ is unexpectedly large, then rubble-pile effects may become important. If Dimorphos's orbit and spin state are sufficiently excited, then surface particle motion is also possible. However, these simulations are limited in their resolution and range of material parameters, so they serve as a demonstration of principle, and Future work is required to fully understand the likelihood and magnitude of surface motion.

21 pages, 19 figures, published in PSJ

References in corpus (9)

• Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems
• Tidal Evolution of Rubble Piles
• Numerical predictions of surface effects during the 2029 close approach of asteroid 99942 Apophis
• The Excited Spin State of Dimorphos Resulting from the DART Impact
• Tidal distortion and disruption of rubble-pile bodies revisited -- Soft-sphere discrete element analyses
• Predictions for the Dynamical States of the Didymos System before and after the Planned DART Impact
• Doubly Synchronous Binary Asteroid Mass Parameter Observability
• The role of fragment shapes in the simulations of asteroids as gravitational aggregates
• A parallel-GPU code for asteroid aggregation problems with angular particles

Cited by in corpus (3)

• Predictions for the Dynamical States of the Didymos System before and after the Planned DART Impact
• Energy Dissipation in Synchronous Binary Asteroids
• Rotation-induced granular motion on the secondary component of binary asteroids: Application to the DART impact on Dimorphos