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

Journal article

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.

Authors: Marchi, S; Levison, HF; Noll, KS; Spencer, JR; Statler, TS

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Association for the Advancement of Science
• Journal: Science
• Volume: 392
• Issue: 6804
• Pages: 1287-1291
• Publication date: 2026-06-18
• Acceptance date: 2026-04-23
• DOI: 10.1126/science.aec0503
• EISSN: 1095-9203
• ISSN: 0036-8075
• Pmid: 42313964
• Language: English