Planetary science: Dimorphos may have been significantly deformed after a Dart collision Natural Astronomy | Nature wallet

A research paper suggests that the asteroid moon Didymos Demorphos may have been significantly deformed after being hit by NASA's Double Asteroid Redirection Experiment (DART).Nature astronomyPublished in This finding suggests that Demorphos may be a fragile debris pile (rubble pile) made up of material released from Didymos.

On September 26, 2022, the DART planetary defense demonstrator collided with Dimorphos, a satellite of the near-Earth asteroid Didymos, shortening Dimorphos' orbital period around Didymos by 33 minutes, completing its mission. While DART has important utility in planetary defense, the spacecraft has also provided information about the internal structure of asteroids and the effects of impacts on their properties.

Now, Sabina Raducan and her colleagues have modeled DART collisions in the modern collision physics code, using realistic constraints on the mechanical and compositional properties of dimorphos provided by the initial DART results. Simulations that better match impact observations indicate that Dimorphos is brittle, has cohesive forces similar to the asteroids Bennu and Ryugu, and has no rocks on its surface. Raducan and colleagues suggest that Demorphos may be a rubble pile formed as a result of rotational mass flow and reaccretion of material ejected from Didymos. The model also suggests that the DART impact did not form an impact crater, but rather distorted the overall shape of the dimorphus (known as large-scale deformation) and caused the surface of the dimorphus to be replenished with material from within, which shows possibility.

Raducan and his colleagues say their findings provide additional clues about the composition and properties of binary asteroids, and could influence future exploration efforts and modification of the orbit of asteroids, including ESA's upcoming Hera mission.

doi:10.1038/s41550-024-02200-3

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