A contact binary satellite of the asteroid (152830) DinkineshOPEN ACCESS 

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. Martin, Brian H. May, Stefano Mottola, Catherine B. Olkin, Martin Pätzold, Joel Wm. Parker, Simon Porter, Frank Preusker, Silvia Protopapa, Dennis C. Reuter, Stuart J. Robbins, Julien Salmon, Amy A. Simon, S. Alan Stern, Jessica M. Sunshine, Ian Wong, Harold A. Weaver, Coralie Adam, Shanti Ancheta, John Andrews, Saadat Anwar, Olivier S. Barnouin, Matthew Beasley, Kevin E. Berry, Emma Birath, Bryce Bolin, Mark Booco, Rich Burns, Pam Campbell, Russell Carpenter, Katherine Crombie, Mark Effertz, Emily Eifert, Caroline Ellis, Preston Faiks, Joel Fischetti, Paul Fleming, Kristen Francis, Ray Franco, Sandy Freund, Claire Gallagher, Jeroen Geeraert, Caden Gobat, Donovan Gorgas, Chris Granat, Sheila Gray, Patrick Haas, Ann Harch, Katie Hegedus, Chris Isabelle, Bill Jackson, Taylor Jacob, Sherry Jennings, David Kaufmann, Brian A. Keeney, Thomas Kennedy, Karl Lauffer, Erik Lessac-Chenen, Rob Leonard, Andrew Levine, Allen Lunsford, Tim Martin, Jim McAdams, Greg Mehall, Trevor Merkley, Graham Miller, Matthew Montanaro, Anna Montgomery, Graham Murphy, Maxwell Myers, Derek S. Nelson, Adriana Ocampo, Ryan Olds, John Y. Pelgrift, Trevor Perkins, Jon Pineau, Devin Poland, Vaishnavi Ramanan, Debi Rose, Eric Sahr, Owen Short, Ishita Solanki, Dale Stanbridge, Brian Sutter, Zachary Talpas, Howard Taylor, Bo Treiu, Nate Vermeer, Michael Vincent, Mike Wallace, Gerald Weigle, Daniel R. Wibben, Zach Wiens, John P. Wilson & Yifan Zhao

Nature, Volume 629, pages 1015–1020, Published: 29 May 2024


“Asteroids with diameters less than about 5 km have complex histories because they are small enough for radiative torques (that is, YORP, short for the Yarkovsky–O’Keefe–Radzievskii–Paddack effect) to be a notable factor in their evolution. (152830) Dinkinesh is a small asteroid orbiting the Sun near the inner edge of the main asteroid belt with a heliocentric semimajor axis of 2.19 au; its S-type spectrum is typical of bodies in this part of the main belt. Here we report observations by the Lucy spacecraft as it passed within 431 km of Dinkinesh. Lucy revealed Dinkinesh, which has an effective diameter of only 720 m, to be unexpectedly complex. Of particular note is the presence of a prominent longitudinal trough overlain by a substantial equatorial ridge and the discovery of the first confirmed contact binary satellite, now named (152830) Dinkinesh I Selam. Selam consists of two near-equal-sized lobes with diameters of 210 m and 230 m. It orbits Dinkinesh at a distance of 3.1 km with an orbital period of about 52.7 h and is tidally locked. The dynamical state, angular momentum and geomorphologic observations of the system lead us to infer that the ridge and trough of Dinkinesh are probably the result of mass failure resulting from spin-up by YORP followed by the partial reaccretion of the shed material. Selam probably accreted from material shed by this event.”