Long-term dust dynamics in Didymos and Dimorphos system: Production, stability, and transport

Abstract

Target of NASA’s DART mission, the system of Didymos and Dimorphos will once again be visited by a space mission — ESA’s Hera mission, scheduled to be launch in 2024. Hera will arrive in the system approximately 4 years after the DART impact, a long period compared to Dimorphos’ orbital period (≃12 h). It is therefore imperative to understand the dynamics of material in this environment on a long timescale. Here, we explore the long-term dynamics of the binary system (65038) Didymos, in the context of the perturbed, planar, circular and restricted 3-body problem. We design an analytical description for a symmetrical top-shaped object, the shape assumed for the Didymos, while the Dimorphos is considered an ellipsoid. In the absence of external effects, we identify seven stable equatorial regions where particles persist for more than a decade. However, in the presence of the solar radiation effect, the lifetime of small particles (≲mm) is in the order of days, being unlikely that Hera spacecraft will encounter clusters of millimeter and sub-millimeter particles in stable equatorial orbits. Nonetheless, large objects may reside in the region for some years, particularly in quasi-satellite orbits, the most stable orbits in the system. Additionally, interplanetary dust impacts onto Didymos populate the region, extending up to a distance of approximately 1500 m from the primary center, with young dust. These impacts are responsible for a transfer of dust mainly from Didymos to Dimorphos. If the interplanetary dust impacts generate metric-sized boulders, they may persist in the system for years, in first sort orbits around Didymos.