151. Orbital Period Change of Dimorphos Due to the DART Kinetic Impact
- Author
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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, 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.
- Subjects
Astrophysics - Earth and Planetary Astrophysics - 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 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., Comment: Accepted by Nature
- Published
- 2023
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