Predictions for the Dynamical States of the Didymos System before and after the Planned DART Impact

Abstract

NASA's Double Asteroid Redirection Test (DART) spacecraft is planned to impact the natural satellite of (65803) Didymos, Dimorphos, around 23:14 UTC on 26 September 2022, causing a reduction in its orbital period that will be measurable with ground-based observations. This test of kinetic impactor technology will provide the first estimate of the momentum transfer enhancement factor $\beta$ at a realistic scale, wherein ejecta from the impact provides an additional deflection to the target. Earth-based observations, the LICIACube spacecraft (to be detached from DART prior to impact), and ESA's follow-up Hera mission to launch in 2024, will provide additional characterization of the deflection test. Together Hera and DART comprise the Asteroid Impact and Deflection Assessment (AIDA) cooperation between NASA and ESA. Here the predicted dynamical states of the binary system upon arrival and after impact are presented. The assumed dynamically relaxed state of the system will be excited by the impact, leading to an increase in eccentricity and slight tilt of the orbit together with enhanced libration of Dimorphos with amplitude dependent on the currently poorly known target shape. Free rotation around the moon's long axis may also be triggered and the orbital period will experience variations from seconds to minutes over timescales of days to months. Shape change of either body due to cratering or mass wasting triggered by crater formation and ejecta may affect $\beta$ but can be constrained through additional measurements. Both BYORP and gravity tides may cause measurable orbital changes on the timescale of Hera's rendezvous.

23 pages, 13 figures, published in PSJ

References in corpus (13)

• Tidal Evolution of Rubble Piles
• SPH calculations of asteroid disruptions: The role of pressure dependent failure models
• The Excited Spin State of Dimorphos Resulting from the DART Impact
• DART Mission Determination of Momentum Transfer: Model of Ejecta Plume Observations
• Doubly Synchronous Binary Asteroid Mass Parameter Observability
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• New multi-part collisional model of the main belt: The contribution to near-Earth asteroids

Cited by in corpus (3)

• Energy Dissipation in Synchronous Binary Asteroids
• Dynamical Evolution of the Didymos-Dimorphos Binary Asteroid as Rubble Piles following the DART Impact
• Rotation-induced granular motion on the secondary component of binary asteroids: Application to the DART impact on Dimorphos