Physical properties of asteroid Dimorphos as derived from the DART impact

Abstract

On September 26, 2022, NASA's Double Asteroid Redirection Test (DART) mission successfully impacted Dimorphos, the natural satellite of the binary near-Earth asteroid (65803) Didymos. Numerical simulations of the impact provide a means to explore target surface material properties and structures, consistent with the observed momentum deflection efficiency, ejecta cone geometry, and ejected mass. Our simulation, which best matches observations, indicates that Dimorphos is weak, with a cohesive strength of less than a few pascals (Pa), similar to asteroids (162173) Ryugu and (101955) Bennu. We find that a bulk density of Dimorphos, rhoB, lower than 2400 kg/m3, and a low volume fraction of boulders (<40 vol%) on the surface and in the shallow subsurface, are consistent with measured data from the DART experiment. These findings suggest Dimorphos is a rubble pile that might have formed through rotational mass shedding and re-accumulation from Didymos. Our simulations indicate that the DART impact caused global deformation and resurfacing of Dimorphos. ESA's upcoming Hera mission may find a re-shaped asteroid, rather than a well-defined crater.

References in corpus (14)

• Successful Kinetic Impact into an Asteroid for Planetary Defense
• Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos
• Orbital Period Change of Dimorphos Due to the DART Kinetic Impact
• Numerical simulations of impacts involving porous bodies: I. Implementing sub-resolution porosity in a 3D SPH Hydrocode
• Ejecta from the DART-produced active asteroid Dimorphos
• SPH calculations of asteroid disruptions: The role of pressure dependent failure models
• Light Curves and Colors of the Ejecta from Dimorphos after the DART Impact
• The Excited Spin State of Dimorphos Resulting from the DART Impact
• Predictions for the Dynamical States of the Didymos System before and after the Planned DART Impact
• Influence of the projectile geometry on the momentum transfer from a kinetic impactor and implications for the DART mission
• Constraining surface properties of asteroid (162173) Ryugu from numerical simulations of Hayabusa2 mission impact experiment
• Reshaping and ejection processes on rubble-pile asteroids by impacts
• The role of fragment shapes in the simulations of asteroids as gravitational aggregates
• Internal rubble properties of asteroid (101955) Bennu

Cited by in corpus (11)

• The Dynamical State of the Didymos System Before and After the DART Impact
• Lessons learned from NASA's DART impact about disrupting rubble-pile asteroids
• Rapid formation of binary asteroid systems post rotational failure: a recipe for making atypically shaped satellites
• The DECam Ecliptic Exploration Project (DEEP). VII. The Strengths of Three Superfast Rotating Main-belt Asteroids from a Preliminary Search of DEEP Data
• High-Speed Boulders and the Debris Field in DART Ejecta
• Delivery of DART Impact Ejecta to Mars and Earth: Opportunity for Meteor Observations
• HyperScout-H: the hyperspectral imager for the ESA Hera mission
• Analytical theory of the spin-orbit state of a binary asteroid deflected by a kinetic impactor
• In-flight calibration of ESA Hera's HyperScout-H imager
• The Material Point Method (MPM) for simulating hypervelocity impact on asteroids
• Secondary impact debris in the Didymos system: what could be observed by Hera?