© The Authors 2025Ferrari, FabioPanicucci, PaoloMerisio, GianmarioPugliatti, MattiaLi, Jian YangFahnestock, EugeneRaducan, SabinaJutzi, MartínSoldini, StefaniaHirabayashi, MasatoshiMerrill, ColbyMichel, PatrickMoreno, FernandoTancredi, GonzaloSunshine, JessicaOrmö, JensHerreros, IsabelAgrusa, HarrisonKaratekin, OzgurZhang, YunChabot, NancyCheng, AndrewRichardson, DerekRivkin, AndrewCampo Bagati, AdrianoFarnham, TonyIvanovski, StavroLucchetti, AlicePajola, MaurizioRossi, AlessandroScheeres, DanielTusberti, Filippo2026-01-132026-01-132025-02-14Nature Communications 16: 1601https://www.nature.com/articles/s41467-025-56551-0https://hdl.handle.net/20.500.12666/1614Source data are provided with this paper. All raw HST data associated with this Article are archived and are publicly available at the Mikulski Archive for Space Telescopes (https://mast.stsci.edu/search/ui/#/hst/results?proposal_id=16674) hosted by the Space Telescope Science Institute. The numerical simulation data, synthetic images, masks, and labels generated in this study have been deposited in the Zenodo database and are publicly available at https://doi.org/10.5281/zenodo.14630436. Source data are provided with this paper.Hypervelocity impacts play a significant role in the evolution of asteroids, causing material to be ejected and partially reaccreted. However, the dynamics and evolution of ejected material in a binary asteroid system have never been observed directly. Observations of Double Asteroid Redirection Test (DART) impact on asteroid Dimorphos have revealed features on a scale of thousands of kilometers, including curved ejecta streams and a tail bifurcation originating from the Didymos system. Here we show that these features result naturally from the dynamical interaction of the ejecta with the binary system and solar radiation pressure. These mechanisms may be used to constrain the orbit of a secondary body, or to investigate the binary nature of an asteroid. Also, they may reveal breakup or fission events in active asteroids, and help determine the asteroid’s properties following an impact event. In the case of DART, our findings suggest that Dimorphos is a very weak, rubble-pile asteroid, with an ejecta mass estimated to be in the range of (1.1-5.5)×107 kg.Authors and Affiliations Department of Aerospace Science and Technology, Politecnico di Milano, Milan, Italy Fabio Ferrari, Paolo Panicucci, Gianmario Merisio, Carmine Giordano & Mattia Pugliatti Planetary Environmental and Astrobiological Research Laboratory (PEARL), School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai, Guangdong, China Jian-Yang Li Jet Propulsion Laboratory, California Institute of Technology, La Cañada Flintridge, CA, USA Eugene G. Fahnestock Space Research and Planetary Sciences, Physikalisches Institut, University of Bern, Bern, Switzerland Sabina D. Raducan & Martin Jutzi Department of Mechanical and Aerospace Engineering, University of Liverpool, Brownlow Hill, UK Stefania Soldini Georgia Institute of Technology, Atlanta, GA, USA Masatoshi Hirabayashi Auburn University, Auburn, AL, USA Masatoshi Hirabayashi Cornell University, Ithaca, NY, USA Colby C. Merrill Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France Patrick Michel & Harrison Agrusa Department of Systems Innovation, School of Engineering, The University of Tokyo, Tokyo, Japan Patrick Michel Instituto de Astrofísica de Andalucía, CSIC, Granada, Spain Fernando Moreno Departamento de Astronomía, Facultad de Ciencias, Udelar, Uruguay Gonzalo Tancredi University of Maryland, College Park, MD, USA Jessica M. Sunshine, Harrison Agrusa, Derek C. Richardson & Tony L. Farnham Department of Astronomy and Department of Geology, University of Maryland, College Park, MD, USA Jessica M. Sunshine Centro de Astrobiologia (CAB), CSIC-INTA, Torrejon de Ardoz, Spain Jens Ormö & Isabel Herreros Royal Observatory of Belgium, Brussels, Belgium Ozgur Karatekin Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA Yun Zhang Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA Nancy L. Chabot, Andrew F. Cheng & Andrew S. Rivkin IUFACyT—DFISTS. Universidad de Alicante, Alicante, Spain Adriano Campo Bagatin INAF—Osservatorio Astronomico di Trieste, Trieste, Italy Stavro Ivanovski INAF-OAPD, Astronomical Observatory of Padova, Padova, Italy Alice Lucchetti, Maurizio Pajola & Filippo Tusberti IFAC-CNR, Sesto Fiorentino, Italy Alessandro Rossi University of Colorado Boulder, Boulder, CO, USA Daniel J. ScheeresengAttribution-NonCommercial-ShareAlike 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-sa/4.0/Aerospace engineeringAsteroidsCometsKuiper beltAstronomy and astrophysicsRings and moonsinfo:eu-repo/semantics/article10.1038/s41467-025-56551-0info:eu-repo/semantics/openAccess