Post-DART impact ejecta re-accumulation on Dimorphos and implications for Hera gravity measurements
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 about 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.
Versions
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BibTeX
@misc{raducan2026postdart,
title = {{Post-DART impact ejecta re-accumulation on Dimorphos and implications for Hera gravity measurements}},
author = {S. D. Raducan and Ö. Karatekin and M. Popescu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.35718},
eprint = {2610.35718},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.35718},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Post-DART impact ejecta re-accumulation on Dimorphos and implications for Hera gravity measurements
AU - S. D. Raducan
AU - Ö. Karatekin
AU - M. Popescu
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.35718
UR - https://arxiv.org/abs/2610.35718
AB - 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 about 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.
ER -