Direct detection of an asteroid's heliocentric deflection: The Didymos system after DART.
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- Record sourced from PubMed, PMID 41790871.
- Also identified by DOI 10.1126/sciadv.aea4259 and PMC identifier 12965290.
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Abstract
In September 2022, NASA's Double Asteroid Redirection Test (DART) spacecraft crashed into Dimorphos and demonstrated the kinetic impact method of protecting Earth from asteroids. A fraction of the impulse delivered to Dimorphos was also imparted onto the Didymos system's barycenter, changing its heliocentric orbit. Here, we present the first-ever measurement of human-caused change in the heliocentric orbit of a celestial body. Thanks to stellar occultation and radar measurements, we estimate that the Didymos system experienced an along-track velocity change of -11.7 ± 1.3 micrometers per second. We constrain the heliocentric momentum enhancement factor for DART at 2.0 ± 0.3 and the bulk densities of Didymos and Dimorphos at 2600 ± 140 and 1540 ± 220 kilograms per cubic meter, respectively. Our results demonstrate that targeting the secondary asteroid in binary systems constitutes a possible strategy for kinetic impact deflection, adding to humanity's planetary defense capabilities.