Orbital period change of Dimorphos due to the DART kinetic impact
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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 minutes was expected if the incident momentum from the DART spacecraft was directly transferred to the asteroid target in a perfectly inelastic collision, but studies of the probable impact conditions and asteroid properties indicated that a considerable momentum enhancement ($\beta$) was possible. In the years prior to impact, we used lightcurve observations to accurately determine the pre-impact orbit parameters of Dimorphos with respect to Didymos. 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 (3$\sigma$) minutes. 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 significant amount of momentum to the asteroid beyond what the DART spacecraft carried.
Thomas , C A , Naidu , S P , Scheirich , P , Moskovitz , N A , Pravec , P , Chesley , S R , Rivkin , A S , Osip , D J , Lister , T A , Benner , L A M , Brozović , M , Contreras , C , Morrell , N , Rożek , A , Kušnirák , P , Hornoch , K , Mages , D , Taylor , P A , Seymour , A D , Snodgrass , C , Jørgensen , U G , Dominik , M , Skiff , B , Polakis , T , Knight , M M , Farnham , T L , Giorgini , J D , Rush , B , Bellerose , J , Salas , P , Armentrout , W P , Watts , G , Busch , M W , Chatelain , J , Gomez , E , Greenstreet , S , Phillips , L , Bonavita , M , Burgdorf , M J , Khalouei , E , Longa-Peña , P , Rabus , M , Sajadian , S , Chabot , N L , Cheng , A F , Ryan , W H , Ryan , E V , Holt , C E & Agrusa , H F 2023 , ' Orbital period change of Dimorphos due to the DART kinetic impact ' , Nature , vol. Accelerated article . https://doi.org/10.1038/s41586-023-05805-2
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DescriptionFunding: U.G.J. acknowledges funding from the Novo Nordisk Foundation Interdisciplinary Synergy Programme grant no. NNF19OC0057374, and from the European Union H2020-MSCA-ITN-2019 grant no. 860470 (CHAMELEON). E.K. is supported by the National Research Foundation of Korea 2021M3F7A1082056. P.L.P. was partly funded by “Programa de Iniciación en Investigación-Universidad de Antofagasta. INI-17-03".
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