On September 26, 2022, NASA’s Double Asteroid Redirection Test (DART) mission successfully impacted Dimorphos, the natural satellite of the near-Earth binary asteroid Didymos. New numerical simulations show that the DART impact triggered global deformation and resurfacing of Dimorphos.
The asteroid moon Dimorphos was seen by NASA’s DART spacecraft 11 seconds before impact. His DRACO imager aboard DART captured this image from a distance of 68 km (42 miles). This image was the last one to include all dimorphos in the field of view. Image credit: NASA/Hopkins Applied Physics Laboratory.
DART was a planetary defense mission that demonstrated the possibility of using kinetic impactors to alter the orbits of asteroids.
The collision was successful and highly effective, resulting in Dimorphos’ orbital period around Didymus being shortened from its original 11 hours and 55 minutes to 33 minutes.
The LICIACube Unit Key Explorer (LUKE) instrument aboard the cubesat took images of the system between 29 seconds and 320 seconds after impact, showing the ejecta stream and other debris that spread for several kilometers from the impact site. revealed a complex pattern.
Furthermore, the dramatic brightening of the Didymos system due to solar illumination of the ejected impact ejecta was observed by ground-based and space-based telescopes for many weeks after the impact.
These three Hubble images capture the breakup of Dimorphos when it was intentionally collided by DART on September 26, 2022. The top panel, taken two hours after impact, shows the ejecta cone (estimated at 1,000 tons of dust). The center frame shows dynamic interactions within the Didymos-Dimorphos binary system that begin to distort the cone of ejecta patterns approximately 17 hours after impact. The most notable structure is a rotating windmill-shaped feature. The windmill is connected to Didymus’s gravitational pull. In the bottom frame, Hubble captures debris being pushed back into the comet-like tail by the pressure of sunlight on tiny dust particles. This spreads out into a column of debris, with the lightest particles traveling fastest and furthest away from the asteroid. The mystery deepens after Hubble recorded the tail splitting into two for several days. Image credit: NASA/ESA/STScI/Jian-Yang Li, PSI/Joseph DePasquale, STScI.
In a new study, University of Bern scientist Sabina Raducan and colleagues use realistic constraints on the mechanical and compositional properties of dimorphos, informed by DART’s initial results, to create a state-of-the-art impact The DART impact was modeled using physical code.
The simulations that best match observations of the impact suggest that Dimorphos is weakly cohesive, similar to asteroids Bennu and Ryugu, and lacks large rocks on its surface.
The researchers suggest that Dimorphos may be a pile of debris formed by the rotational shedding and re-accumulation of material ejected from Didymos.
Their model also suggests that DART’s impact may not have created an impact crater, but instead may have changed the shape of the moon as a whole, a process known as global deformation, which could have been caused by material from within. It also indicates that it may have caused the resurfacing of Dimorphos.
The discovery provides further insight into the formation and characteristics of binary asteroids and could have implications for future exploration, including ESA’s Hera mission and asteroid deflection efforts.
“ESA’s future Hera mission may discover reformed asteroids rather than well-defined craters,” the authors concluded.
their paper It was published in the magazine natural astronomy.
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SD Raducan other. Physical properties of the asteroid Dimorphos obtained from the DART impact. Nat Astron, published online on February 26, 2024. doi: 10.1038/s41550-024-02200-3
Source: www.sci.news
