Orbital period change of Dimorphos due to the DART kinetic impact

Thomas, Cristina A., Naidu, Shantanu P., Scheirich, Peter, Moskovitz, Nicholas A., Pravec, Petr, Chesley, Steven R., Rivkin, Andrew S., Osip, David J., Lister, Tim A., Benner, Lance A. M., Brozović, Marina, Contreras, Carlos, Morrell, Nidia, Rożek, Agata, Kušnirák, Peter, Hornoch, Kamil, Mages, Declan, Taylor, Patrick A., Seymour, Andrew D., Snodgrass, Colin, Jørgensen, Uffe G., Dominik, Martin, Skiff, Brian, Polakis, Tom, Knight, Matthew M., Farnham, Tony L., Giorgini, Jon D., Rush, Brian, Bellerose, Julie, Salas, Pedro, Armentrout, William P., Watts, Galen, Busch, Michael W., Chatelain, Joseph, Gomez, Edward ORCID: https://orcid.org/0000-0001-5749-1507, Greenstreet, Sarah, Phillips, Liz, Bonavita, Mariangela, Burgdorf, Martin J., Khalouei, Elahe, Longa-Peña, Penélope, Rabus, Markus, Sajadian, Sedighe, Chabot, Nancy L., Cheng, Andrew F., Ryan, William H., Ryan, Eileen V., Holt, Carrie E. and Agrusa, Harrison F. 2023. Orbital period change of Dimorphos due to the DART kinetic impact. Nature 616 , pp. 448-451. 10.1038/s41586-023-05805-2

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Abstract

The Double Asteroid Redirection Test (DART) spacecraft successfully performed the first test of a kinetic impactor for asteroid deflection by impacting Dimorphos, the secondary of near-Earth binary asteroid (65803) Didymos, and changing the orbital period of Dimorphos. A change in orbital period of approximately 7 min was expected if the incident momentum from the DART spacecraft was directly transferred to the asteroid target in a perfectly inelastic collision1, but studies of the probable impact conditions and asteroid properties indicated that a considerable momentum enhancement (β) was possible2, 3. In the years before impact, we used lightcurve observations to accurately determine the pre-impact orbit parameters of Dimorphos with respect to Didymos4–6. Here we report the change in the orbital period of Dimorphos as a result of the DART kinetic impact to be −33.0 ± 1.0 (3σ) min. Using new Earth-based lightcurve and radar observations, two independent approaches determined identical values for the change in the orbital period. This large orbit period change suggests that ejecta contributed a substantial amount of momentum to the asteroid beyond what the DART spacecraft carried.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/, Type: open-access
Publisher:	Nature Research
ISSN:	0028-0836
Date of First Compliant Deposit:	20 April 2023
Date of Acceptance:	7 February 2023
Last Modified:	05 May 2023 20:08
URI:	https://orca.cardiff.ac.uk/id/eprint/158958

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