“Intriguing” discovery in new asteroid images from NASA mission

Dinkinesh a small asteroid that NASA’s Lucy mission visited last week, continues to surprise.

Lucy passed by the space rock, located in the main asteroid belt between Mars and Jupiter, on Nov. 1 as part of a test of the spacecraft’s equipment before tackling the mission’s main objective: surveying the Trojan asteroid swarms around Jupiter. . The Dinkinesh flyover, which means “wonderful” in the Ethiopian Amharic language, was only added to Lucy’s itinerary in January.

But the first images captured by Lucy’s instruments showed there was more to the shadowy asteroid than expected. At first, the images suggested that the space rock was part of a binary pair, with a smaller asteroid orbiting Dinkinesh.

However, additional images taken by the probe shortly after the flyby’s closest approach have now revealed that the smaller asteroid is actually a contact binary – two smaller space rocks touching each other.

Lucy came within 425 kilometers of the asteroid’s surface during its closest approach, which was when the first images were taken. The second batch of images revealing the contact binary, shared by NASA on Tuesday (7), was obtained six minutes later, around 1,630 kilometers away.

“Contact binaries appear to be quite common in the solar system,” said John Spencer, associate scientist for the Lucy project at the Southwest Research Institute, in a statement.

“We haven’t seen many up close and we’ve never seen any orbiting another asteroid. We were intrigued by strange variations in Dinkinesh’s brightness that we saw as we approached, which gave us a hint that Dinkinesh might have a moon of some kind, but we never suspected anything so bizarre!”

Solving an asteroid riddle

The approach was designed primarily to help the Lucy spacecraft test its terminal tracking system, which allows the spacecraft to autonomously locate the space rock and keep it in sight while flying at 4.5 kilometers per second. The system exceeded expectations, allowing astronomers to discover Dinkinesh’s unexpected companion rock.

“It’s intriguing to say the least,” Hal Levison, Lucy’s principal investigator at the Southwest Research Institute, said in a statement. “I would never have expected a system like this. In particular, I don’t understand why the two satellite components are similar in size. This will be fun for the scientific community to discover.”

Data from the flyby is still being transmitted from the spacecraft to the mission team.

“It’s truly wonderful when nature surprises us with a new puzzle,” said Tom Statler, NASA’s Lucy program scientist. “Great science leads us to ask questions we never knew we needed to ask.”

Setting a course for the Trojans

Lucy’s next encounter will be with another main-belt asteroid called Donaldjohanson in 2025. And then, the spacecraft will head off to see the Trojans.

Trojan asteroids, named after Greek mythology, orbit the sun in two clusters – one that is in front of Jupiter, the largest planet in our solar system, and a second that is behind it. Too distant to be seen in detail with telescopes, the asteroids will get closer when Lucy reaches the Trojans in 2027.

The mission borrows its name from the Lucy fossil, the remains of an ancient human ancestor discovered in Ethiopia in 1974. The skeleton helped researchers piece together aspects of human evolution, and members of NASA’s Lucy team hope their mission achieves a feat similar to the history of our solar system.

Asteroids are like fossils, representing the material left over after the formation of giant planets in our solar system, including Jupiter, Saturn, Uranus and Neptune.