After the Southwest Research Institute-led Lucy mission flew past the asteroid Dinkinesh, the team discovered that it is even more “marvelous” as its newly discovered satellite is now shown to be a double-lobed moonlet. As NASA’s Lucy spacecraft continued to return data acquired during its first asteroid encounter on Nov. 1, 2023, the team discovered that Dinkinesh’s surprise satellite is itself a contact binary, made of two smaller objects touching each other.
In the first image of Dinkinesh and its satellite taken at closest approach, the two lobes of the contact binary lined up, one behind the other, appearing to be one body from Lucy’s point of view. When the team downlinked additional images captured after the closest encounter, the data revealed that Dinkenesh has a double moonlet.
“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 SwRI. “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!”