Asteroid Donaldjohanson formed 150 million years ago

Recent research by the Southwest Research Institute suggests that the asteroid Donaldjohanson formed around 150 million years ago. This likely occurred after a larger parent asteroid broke apart. The study highlights that Donaldjohanson’s orbit and rotation have changed significantly over time. NASA's Lucy spacecraft is scheduled to fly by Donaldjohanson on April 20, 2025. The mission will collect data about the asteroid's shape, surface, and cratering history. This information could help scientists understand how the asteroid evolved. Dr. Simone Marchi, a lead researcher on the Lucy mission, noted that Donaldjohanson appears to be unusual compared to other asteroids. David Vokrouhlický, a co-author of the study, mentioned that the asteroid may have an elongated shape and a slow rotation due to thermal effects acting on it over time. Donaldjohanson is composed of silicate rocks and might include clays and organic materials. It is part of a family of asteroids formed from the debris of a larger asteroid in the inner main belt. This group is closely related to the orbits of near-Earth asteroids like Bennu and Ryugu. The Lucy mission aims to visit a total of 11 asteroids over 12 years. These explorations are important for understanding the history of the solar system. Dr. Hal Levison, the mission's principal investigator, emphasized that studying these ancient asteroids offers insights into the formation of planets. Donaldjohanson is named after the paleontologist who discovered the famous fossil known as Lucy, which has provided important information about human origins. This asteroid will be visited while its namesake is still living, making it unique.