학술논문
Orbital Period Change of Dimorphos Due to the DART Kinetic Impact
Document Type
Working Paper
Author
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.; Agrusa, Harrison F.
Source
Subject
Language
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
Comment: Accepted by Nature