Journal Article

Mechanical properties of rubble pile asteroids (Dimorphos, Itokawa, Ryugu, and Bennu) through surface boulder morphological analysis

Trigo-Rodriguez, Josep M., Stott, Alexander, Rivkin, Andrew S., Robin, Colas Q., Jawin, Erica R., Lucchetti, Alice, Daly, R. Terik, Cuervo, Gabriela, Parro, Laura M., Murdoch, Naomi, Barnouin, Olivier S., Sunday, Cecily, Mimoun, David, Vincent, Jean-Baptiste, Ernst, Carolyn M., Michel, Patrick, Duchene, Alexia, Raducan, Sabina D., Pajola, Maurizio, Hirabayashi, Masatochi, Vivet, Damien, Chabot, Nancy L.

2024

Overview

Planetary defense efforts rely on estimates of the mechanical properties of asteroids, which are difficult to constrain accurately from Earth. The mechanical properties of asteroid material are also important in the interpretation of the Double Asteroid Redirection Test (DART) impact. Here we perform a detailed morphological analysis of the surface boulders on Dimorphos using images, the primary data set available from the DART mission. We estimate the bulk angle of internal friction of the boulders to be 32.7 ± 2. 5° from our measurements of the roundness of the 34 best-resolved boulders ranging in size from 1.67–6.64 m. The elongated nature of the boulders around the DART impact site implies that they were likely formed through impact processing. Finally, we find striking similarities in the morphology of the boulders on Dimorphos with those on other rubble pile asteroids (Itokawa, Ryugu and Bennu). This leads to very similar internal friction angles across the four bodies and suggests that a common formation mechanism has shaped the boulders. Our results provide key inputs for understanding the DART impact and for improving our knowledge about the physical properties, the formation and the evolution of both near-Earth rubble-pile and binary asteroids. Planetary Defense efforts rely on estimates of asteroids’ mechanical properties, which are difficult to obtain accurately from Earth. Here, authors compare images from space missions to the rubble-pile asteroids Dimorphos, Itokawa, Ryugu, and Bennu and study such properties through boulders on their surface.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 639/33/445/215 / 639/33/445/848 / 704/445/848 / Apollo asteroids / Asteroid missions / Asteroids / Astrophysics / Boulders / Earth / Earth and Planetary Astrophysics / Estimates / Friction / Humanities and Social Sciences / Impact analysis / Internal friction / Mechanical properties / Mechanics / Morphology / multidisciplinary / Physical properties / Physics / Planetary defense / Planetary evolution / Roundness / Science / Science (multidisciplinary) / Sciences of the Universe / Solid mechanics / Space missions