The Lucy flyby of (52246) Donaldjohanson: A bilobed asteroid with tumbling rotation
- Simone Marchi
- Harold F. Levison
- Keith S. Noll
- John R. Spencer
- Thomas S. Statler
- Olivier S. Barnouin
- James F. Bell
- 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
- Victoria E. Hamilton
- Carly Howett
- Hannah H. Kaplan
- Katherine Kretke
- Tod R. Lauer
- Brian H. May
- Stefano Mottola
- Catherine B. Olkin
- Martin Pätzold
- Joel Wm. Parker
- Frank Preusker
- Silvia Protopapa
- Dennis C. Reuter
- Stuart J. Robbins
- Julien Salmon
- Amy A. Simon
- S. Alan Stern
- Jessica M. Sunshine
- David Vokrouhlický
- Harold A. Weaver
- Harrison Agrusa
- Emily S. Costello
- Masatoshi Hirabayashi
- Fiona Nichols-Fleming
- Jennifer E. C. Scully
- Anne Verbiscer
- Coralie Adam
- John Andrews
- Kevin E. Berry
- Emma Birath
- Rich Burns
- Russell Carpenter
- Mark Effertz
2026-06-18
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.