Diverse configurations of binary asteroids explained by multi-generation satellites

Binary asteroid systems are ubiquitous in the Solar System. Many of them originate from rotational breakup, where an asteroid’s spin-up triggers mass shedding and subsequent satellite formation from a transient debris disk. While prolate satellites on compact orbits are expected in this scenario, recent space missions revealed remarkable diversity of binary configurations, such as the contact-binary satellite Selam on a wide orbit around (152830) Dinkinesh. Here we show that multiple episodes of mass shedding and the resulting multi-generation satellites provide a unified framework for these diverse configurations. We find that a pre-existing satellite can strongly influence subsequent satellite formation pathways through disk-satellite and inter-satellite interactions. This mechanism explains the dynamical histories of the Dinkinesh system and several triple systems. Our analysis indicates that about 44% of known binaries have configurations indicative of multi-satellite histories, suggesting that a significantly greater diversity of binary asteroid configurations remains to be revealed.