The Lucy flyby of (52246) Donaldjohanson: A bilobed asteroid with tumbling rotation

S Simone Marchi H Harold F. Levison (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) K Keith S. Noll (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) J John R. Spencer (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) T Thomas S. Statler (NASA Headquarters, Washington, DC, USA.) O Olivier S. Barnouin (Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.) J James F. Bell (School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.) E Edward B. Bierhaus (Lockheed Martin Space, Littleton, CO, USA.) R Richard Binzel (Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA.) W William F. Bottke D Daniel Britt (Department of Physics, University of Central Florida, Orlando, FL, USA.) M Michael E. Brown (Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.) M Marc W. Buie (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) P Philip R. Christensen (School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.) N Neil Dello Russo (Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.) J Joshua P. Emery (Lowell Observatory, Flagstaff, AZ, USA.) W William M. Grundy (Lowell Observatory, Flagstaff, AZ, USA.) V Victoria E. Hamilton (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) C Carly Howett (Planetary Science Institute, Tucson, AZ, USA.) H Hannah H. Kaplan (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) K Katherine Kretke (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) T Tod R. Lauer (National Optical-Infrared Astronomy Research Laboratory, National Science Foundation, Tucson, AZ, USA.) B Brian H. May (London Stereoscopic Company, London, UK.) S Stefano Mottola (Institute of Space Research, German Aerospace Center, Berlin, Germany.) C Catherine B. Olkin (Fifth West Consulting, Niwot, CO, USA.) M Martin Pätzold (Freies Institut für Planetenforschung Köln, Cologne, Germany.) J Joel Wm. Parker (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) F Frank Preusker (Institute of Space Research, German Aerospace Center, Berlin, Germany.) S Silvia Protopapa (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) D Dennis C. Reuter (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) S Stuart J. Robbins (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) J Julien Salmon (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) A Amy A. Simon (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) S S. Alan Stern (Space Sector, Southwest Research Institute, Boulder, CO, USA.) J Jessica M. Sunshine (Department of Astronomy, Department of Geological, Environmental and Planetary Sciences, University of Maryland, College Park, MD, USA.) D David Vokrouhlický (Astronomical Institute, Charles University, Prague, Czech Republic.) H Harold A. Weaver (Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.) H Harrison Agrusa (Université Côte d’Azur, Observatoire de la Côte d’Azur, French National Center for Scientific Research, Laboratoire Lagrange, Nice, France.) E Emily S. Costello (Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, USA.) M Masatoshi Hirabayashi (Daniel Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA, USA.) F Fiona Nichols-Fleming (Center for Earth and Planetary Studies, Smithsonian National Air and Space Museum, Washington, DC, USA.) J Jennifer E. C. Scully (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.) A Anne Verbiscer (Department of Astronomy, University of Virginia, Charlottesville, VA, USA.) C Coralie Adam (Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.) J John Andrews (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) K Kevin E. Berry (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) E Emma Birath (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) R Rich Burns (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) R Russell Carpenter (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) M Mark Effertz (Lockheed Martin Space, Littleton, CO, USA.) K Kristen Francis (Lockheed Martin Space, Littleton, CO, USA.) J Jeroen Geeraert (Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.) S Sheila Gray (Lockheed Martin Space, Littleton, CO, USA.) K Katie Hegedus (Lockheed Martin Space, Littleton, CO, USA.) D David Kaufmann (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) B Brian A. Keeney (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) T Thomas Kennedy (Lockheed Martin Space, Littleton, CO, USA.) J Jim McAdams (Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.) M Matthew Montanaro (Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, USA.) J Jon Pineau (Stellar Solutions, Denver, CO, USA.) D Devin Poland (NASA Goddard Space Flight Center, Greenbelt, MD, USA.) E Eric Sahr (Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.) I Ishita Solanki (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.) D Dale Stanbridge (Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.) B Brian Sutter (Lockheed Martin Space, Littleton, CO, USA.) M Michael Vincent (Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.)

Abstract

The main belt asteroid (52246) Donaldjohanson (DJ) is a likely member of the Erigone asteroid family. This implies that DJ is a fragment of a larger parent body that was destroyed in a collision about 155 million years ago. We report observations taken during a flyby of DJ by the Lucy spacecraft. We found that DJ is composed of two heavily cratered lobes, connected by a smoother neck, with overall dimensions 8.8 kilometers (km) by 4.4 km by 3.1 km. The crater density is consistent with the Erigone family’s age, except for craters <0.4 km, which have been preferentially erased. DJ rotates slowly in a tumbling state, likely owing to spin-down by radiative forces. Surface spectra show iron-bearing phyllosilicates, indicating moderate aqueous evolution on the parent body.

Article Details

Journal Science
Volume / Issue Vol. 392, Issue 6804
Published June 18, 2026
Pages 1287-1291
ISSN 0036-8075
Publisher American Association for the Advancement of Science

Journal Info

Science

American Association for the Advancement of Science

ISSN: 0036-8075 Social Sciences

Authors (66)

S

Simone Marchi

H

Harold F. Levison

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

K

Keith S. Noll

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

J

John R. Spencer

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

T

Thomas S. Statler

NASA Headquarters, Washington, DC, USA.

O

Olivier S. Barnouin

Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.

J

James F. Bell

School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.

E

Edward B. Bierhaus

Lockheed Martin Space, Littleton, CO, USA.

R

Richard Binzel

Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA.

W

William F. Bottke

D

Daniel Britt

Department of Physics, University of Central Florida, Orlando, FL, USA.

M

Michael E. Brown

Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.

M

Marc W. Buie

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

P

Philip R. Christensen

School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.

N

Neil Dello Russo

Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.

J

Joshua P. Emery

Lowell Observatory, Flagstaff, AZ, USA.

W

William M. Grundy

Lowell Observatory, Flagstaff, AZ, USA.

V

Victoria E. Hamilton

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

C

Carly Howett

Planetary Science Institute, Tucson, AZ, USA.

H

Hannah H. Kaplan

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

K

Katherine Kretke

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

T

Tod R. Lauer

National Optical-Infrared Astronomy Research Laboratory, National Science Foundation, Tucson, AZ, USA.

B

Brian H. May

London Stereoscopic Company, London, UK.

S

Stefano Mottola

Institute of Space Research, German Aerospace Center, Berlin, Germany.

C

Catherine B. Olkin

Fifth West Consulting, Niwot, CO, USA.

M

Martin Pätzold

Freies Institut für Planetenforschung Köln, Cologne, Germany.

J

Joel Wm. Parker

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

F

Frank Preusker

Institute of Space Research, German Aerospace Center, Berlin, Germany.

S

Silvia Protopapa

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

D

Dennis C. Reuter

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

S

Stuart J. Robbins

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

J

Julien Salmon

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

A

Amy A. Simon

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

S

S. Alan Stern

Space Sector, Southwest Research Institute, Boulder, CO, USA.

J

Jessica M. Sunshine

Department of Astronomy, Department of Geological, Environmental and Planetary Sciences, University of Maryland, College Park, MD, USA.

D

David Vokrouhlický

Astronomical Institute, Charles University, Prague, Czech Republic.

H

Harold A. Weaver

Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.

H

Harrison Agrusa

Université Côte d’Azur, Observatoire de la Côte d’Azur, French National Center for Scientific Research, Laboratoire Lagrange, Nice, France.

E

Emily S. Costello

Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, USA.

M

Masatoshi Hirabayashi

Daniel Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA, USA.

F

Fiona Nichols-Fleming

Center for Earth and Planetary Studies, Smithsonian National Air and Space Museum, Washington, DC, USA.

J

Jennifer E. C. Scully

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.

A

Anne Verbiscer

Department of Astronomy, University of Virginia, Charlottesville, VA, USA.

C

Coralie Adam

Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.

J

John Andrews

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

K

Kevin E. Berry

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

E

Emma Birath

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

R

Rich Burns

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

R

Russell Carpenter

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

M

Mark Effertz

Lockheed Martin Space, Littleton, CO, USA.

K

Kristen Francis

Lockheed Martin Space, Littleton, CO, USA.

J

Jeroen Geeraert

Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.

S

Sheila Gray

Lockheed Martin Space, Littleton, CO, USA.

K

Katie Hegedus

Lockheed Martin Space, Littleton, CO, USA.

D

David Kaufmann

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

B

Brian A. Keeney

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

T

Thomas Kennedy

Lockheed Martin Space, Littleton, CO, USA.

J

Jim McAdams

Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.

M

Matthew Montanaro

Center for Imaging Science, Rochester Institute of Technology, Rochester, NY, USA.

J

Jon Pineau

Stellar Solutions, Denver, CO, USA.

D

Devin Poland

NASA Goddard Space Flight Center, Greenbelt, MD, USA.

E

Eric Sahr

Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.

I

Ishita Solanki

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.

D

Dale Stanbridge

Flight Dynamics Interplanetary Department, KinetX, Littleton, CO, USA.

B

Brian Sutter

Lockheed Martin Space, Littleton, CO, USA.

M

Michael Vincent

Solar System Science and Exploration Division, Southwest Research Institute, Boulder, CO, USA.