Year: 2026
Type: article
Abstract: Small planetary bodies record the processes that shaped the Solar System, but their surfaces and interiors often evolve in unexpected ways. Deimos, the potato-shaped, 12-km-diameter outer satellite of Mars, has a strikingly smooth surface covered by fine regolith, in contrast to its heavily cratered and grooved sibling, 22-km-diameter Phobos. Moreover, Deimos’s topography is dominated by a single large south-polar depression, whose formation we simulate to constrain the moon’s interior and surface geomechanical properties and to explain the origin and distribution of its regolith. Here we find that an oblique impact by a 320-m-diameter projectile can quantitatively account for this depression, the global regolith layer and surface features such as bright streaks and crater infill. Our results show that Deimos’s upper layers are extremely weak and that its interior is highly porous and dissipative, resembling the recently visited rubble-pile asteroids rather than lunar regolith. This suggests that small dark moons and asteroids, despite their specific histories, may converge on similar physical states.
Source: Nature Astronomy
Institutions: University of Bern, Vrije Universiteit Brussel, Royal Observatory of Belgium, Centre National de la Recherche Scientifique, Université Côte d'Azur, Centre National d'Études Spatiales, Lagrange Laboratory, Observatoire de la Côte d’Azur, University of Arizona, Johns Hopkins University Applied Physics Laboratory, The University of Tokyo, National Institute for Laser Plasma and Radiation Physics, Institute of Space Science - INFLPR Subsidiary, University of Craiova
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $12,690
Funders: National Science Foundation, National Aeronautics and Space Administration, University of Bern, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Centre National d’Etudes Spatiales, Fonds Wetenschappelijk Onderzoek, Universitetet i Oslo, Vlaamse regering, Japan Society for the Promotion of Science
Awards: Integrating Simulations and Mission Data to Uncover Meteorite Formation from Asteroid Collisions, Understanding of the diversity of prebiotic chemistries and emergence of molecular systems in various planetary environments in the Solar System, G3536587230, Studies of impact processes on small bodies: implications for asteroid formation and upcoming space missions, G6878308038
OpenAlex ID: W7203694447