NASA’s Lucy spacecraft’s recent exploration of asteroid Dinkinesh not only highlighted the asteroid’s internal complexities but also led to a fascinating discovery: the formation of a double moon, Selam. This rare configuration, known as a contact binary, formed from debris orbiting Dinkinesh after a significant geological event.
“These features tell us that Dinkinesh has some strength, and they let us do a little historical reconstruction to see how this asteroid evolved,” said Levison. “It broke, things moved apart and formed a disk of material during that failure, some of which rained back onto the surface to make the ridge.”
Stereo movie of Selam from NASA’s Lucy spacecraft flyby on Nov. 1, 2023. Credit: NASA/GSFC/SwRI/Johns Hopkins APL/NOIRLab/Brian May/Claudia ManzoniDinkinesh and its satellite are the first two of 11 asteroids that Lucy’s team plans to explore over its 12-year journey. After skimming the inner edge of the main asteroid belt, Lucy is now heading back toward Earth for a gravity assist in December 2024.
Reference: “A contact binary satellite of the asteroid Dinkinesh” by Harold F. Levison, Simone Marchi, Keith S. Noll, John R. Spencer, Thomas S. Statler, James F. Bell III, Edward B. Bierhaus, Richard Binzel, William F. Bottke, Daniel Britt, Michael E. Brown, Marc W. Buie, Philip R. Christensen, Neil Dello Russo, Joshua P. Emery, William M. Grundy, Matthias Hahn, Victoria E. Hamilton, Carly Howett, Hannah Kaplan, Katherine Kretke, Tod R. Lauer, Claudia Manzoni, Raphael Marschall, Audrey C.