Asteroid Demorphos looks very different after NASA's DART mission removed it

In September 2022, A A NASA spacecraft collided with a small asteroid To remove it from its orbital path. The mission was A Success in testing the asteroid deflection method That might come in handy one day, but instead of leaving an impact crater behind, the orbital collision completely changed the shape of the target asteroid, revealing its replaceable composition.

A team of researchers simulated the impact of NASA's Double Asteroid Redirection Test, or DART, to reveal how Dimorphos, a 558-foot-wide (170-meter) space rock orbiting its larger, 2,625-foot-wide (800-meter) planet, was diverted. Meter) Comrade Didymus. In new Stady Published in natural astronomy, Simulations show that the impact resulted in the asteroid Demorphos being significantly reshaped and resurfaced.

“Our simulations revealed that Dimorphos is probably a rubble pile asteroid,” Sabina Raducan, a planetary scientist at the University of Bern, Switzerland, and lead author of the study, told Gizmodo in an email. “Before DART arrived at Dimorphos, we didn't know what to expect because the system is so far from Earth.”

NASA's 1,340-pound spacecraft collided with the moon on September 26, 2022, after a 10-month journey to the binary asteroid system. Data sets collected by ground-based optical and radio telescopes show that after the impact, Demorphos' orbital period around Didymos shortened from 11 hours and 55 minutes to 11 hours and 23 minutes.

Using the smoothed particle hydrodynamics (SPH) impact code, the team ran 250 simulations to reproduce the asteroid's first two hours after impact. Scientists estimate that 1% of Dimorphos's entire mass was ejected into space after its collision with the DART spacecraft, and about 8% of its mass was moved around its body.

The results show not only what might have happened to the asteroid after the spacecraft hit it, but also the composition of dimorphos itself. The study indicates that the asteroid is a pile of rubble held together due to its weak gravity rather than its cohesive strength. Therefore, the DART impact created much wider cone-shaped ejecta or column of material that stretched up to 160 degrees, and continued to expand after the impact due to the weak gravity holding the asteroid together and the low cohesion of the material.

The study results also indicate that the small asteroid Demorphos likely formed from material discarded by Didymos, which was reassembled and gravitationally bound to orbit the larger asteroid like a small moon. “These results provide clues about the prevalence and properties of similar binary systems in our solar system, contributing to our broader understanding of the history of their formation and evolution,” Raducan said.

The European Space Agency (ESA) is planning a follow-up mission to the binary pair of space rocks to take a closer look at the changes made to Dimorphos after its encounter with DART. It is scheduled to be launched by the European Space Agency Hera's mission In 2024, which will meet Didymos and its moon in 2026.

Follow-up observations could provide clues about how asteroids formed and help better inform ways to deflect asteroids to prepare for a potential collision with Earth.

“The implication for planetary defense is that small asteroids made up of piles of rubble, such as dimorphos, are very effective at deflection, and kinetic impact technology would be a suitable deflection mechanism,” Raducan said. “However, before attempting to deviate, a reconnaissance mission will likely be necessary to accurately assess the asteroid's properties.”

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