Journal Article

Physical properties of asteroid Dimorphos as derived from the DART impact

Jutzi, M., Luther, R., Tusberti, F., Farnham, T. L., Robin, C. Q., Zinzi, A., Raducan, S. D., Zhang, Y., Li, J. -Y., Kumamoto, K. M., Manzoni, C., Hirabayashi, M., Ferrari, F., Lucchetti, A., Agrusa, H. F., Owen, M., Rossi, A., May, B. H., Fahnestock, E. G., Davison, T. M., Ernst, C. M., Barnouin, O., Dotto, E., Daly, R. T., Ormö, J., Wünnemann, K., Pajola, M., Hasselmann, P. H., Syal, M. Bruck, Herreros, I., Barbee, B. W., Rivkin, A. S., Murdoch, N., Nakano, R., Ivanovski, S., Epifani, E. Mazzotta, Sánchez, P., Pravec, P., Cheng, A. F., Collins, G. S., Michel, P., Chabot, N. L.

2024

Overview

On 26 September 2022, NASA’s Double Asteroid Redirection Test (DART) mission successfully impacted Dimorphos, the natural satellite of the binary near-Earth asteroid (65803) Didymos. Numerical simulations of the impact provide a means to find the surface material properties and structures of the target that are consistent with the observed momentum deflection efficiency, ejecta cone geometry and ejected mass. Our simulation that best matches the observations indicates that Dimorphos is weak, with a cohesive strength of less than a few pascals, like asteroids (162173) Ryugu and (101955) Bennu. We find that the bulk density of Dimorphos ρ B is lower than ~2,400 kg m − 3 and that it has a low volume fraction of boulders (≲40 vol%) on the surface and in the shallow subsurface, which are consistent with data measured by the DART experiment. These findings suggest that Dimorphos is a rubble pile that might have formed through rotational mass shedding and reaccumulation from Didymos. Our simulations indicate that the DART impact caused global deformation and resurfacing of Dimorphos. ESA’s upcoming Hera mission may find a reshaped asteroid rather than a well-defined crater. Numerical simulations of the DART impact on asteroid Didymos’s moon Dimorphos highlight its rubble-pile nature with a low bulk density and boulder volume fraction. These results indicate that Dimorphos formed from reaccumulated material shed from Didymos via rotation or impact.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Springer Nature
• Subject: 639/33/34 / 639/33/445/848 / asteroids / Astronomy / ASTRONOMY AND ASTROPHYSICS / Astrophysics / Astrophysics and Cosmology / comets / Earth and Planetary Astrophysics / Kuiper belt / Physical properties / Physics / Physics and Astronomy / Sciences of the Universe / Simulation