It turns out there is more to the “marvelous” asteroid Dinkinesh and its newly discovered satellite than first meets the eye. As NASA’s Lucy spacecraft continued to return data of its first asteroid encounter on Nov. 1, 2023, the team was surprised to discover that Dinkinesh’s unanticipated satellite is, itself, a contact binary – that is, it is made of two smaller objects touching each other.
NASA/Goddard/SwRI/Johns Hopkins APL
“Contact binaries seem to be fairly common in the solar system,” said John Spencer, Lucy deputy project scientist, of the Boulder, Colorado, branch of the San-Antonio-based Southwest Research Institute. “We haven’t seen many up-close, and we’ve never seen one orbiting another asteroid. We’d been puzzling over odd variations in Dinkinesh’s brightness that we saw on approach, which gave us a hint that Dinkinesh might have a moon of some sort, but we never suspected anything so bizarre!”
Lucy’s primary goal is to survey the never-before-visited Jupiter Trojan asteroids. This first encounter with a small, main belt asteroid was only added to the mission in January 2023, primarily to serve as an in-flight test of the system that allows the spacecraft to continually track and image its asteroid targets as it flies past at high speed. The excellent performance of that system at Dinkinesh allowed the team to capture multiple perspectives on the system, which enabled the team to better understand the asteroids’ shapes and make this unexpected discovery.
“It is puzzling, to say the least,” said Hal Levison, principal investigator for Lucy, also from Southwest Research Institute. “I would have never expected a system that looks like this. In particular, I don’t understand why the two components of the satellite have similar sizes. This is going to be fun for the scientific community to figure out.”
This second image was taken about 6 minutes after closest approach from a distance of approximately 1,010 miles (1,630 km). The spacecraft traveled around 960 miles (1,500 km) between the two released images.
“It’s truly marvelous when nature surprises us with a new puzzle,” said Tom Statler, Lucy program scientist from NASA Headquarters in Washington. “Great science pushes us to ask questions that we never knew we needed to ask.”
Overall graphic, NASA/Goddard/SwRI; Inset “A,” NASA/Goddard/SwRI/Johns Hopkins
Lucy’s principal investigator is based out of the Boulder, Colorado, branch of Southwest Research Institute, headquartered in San Antonio. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin Space in Littleton, Colorado, built and operates the spacecraft. Lucy is the 13th mission in NASA’s Discovery Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for the Science Mission Directorate at NASA Headquarters in Washington.
For more information about NASA’s Lucy mission, visit:
By Katherine Kretke
Southwest Research Institute, San Antonio
Media Contact:
NASA’s Goddard Space Flight Center, Greenbelt, Md.