Work

Post-DART impact ejecta re-accumulation on Dimorphos and implications for Hera gravity measurements

Year: 2026

Type: article

Abstract: Context. The DART impact might have substantially modified the surface and near-surface structure of Dimorphos, affecting the morphology and gravity field that is to be measured by ESA’s Hera mission. Aims. We investigate the post-impact redistribution of ejecta and its dependence on the assumed internal structure of Dimorphos. Methods. We performed high-resolution SPH simulations of the DART impact into two low-cohesion rubble-pile models, with and without a large central boulder. We followed the processes of ejecta re-accumulation and gravity evolution for six hours. Results. The impact ejects ≈13% of Dimorphos’s mass, most of which is re-accreted, producing near-global resurfacing. The ejecta blanket exceeds 8 m around the impact depression but is only a few tens of centimetres thick near the antipode, with similar large-scale deposition in both interior models. Local gravity changes reach about 10% of the pre-impact value. The central boulder affects the surface gravity only within the impact depression, where the removal of overlying material enhances its gravitational contribution. Conclusions. Hera will observe a surface and gravity field substantially modified by DART, which must be considered when interpreting measurements in terms of the internal structure of Dimorphos.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202662657

Authors: S. D. Raducan, Ö. Karatekin, M. Popescu

Institutions: Vrije Universiteit Brussel, Royal Observatory of Belgium, 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: Space and Planetary Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865

Funders: Fonds Wetenschappelijk Onderzoek, Vlaamse regering