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arXiv · 2006.13901

A Pluto-Charon Concerto: An Impact on Charon as the Origin of the Small Satellites

Benjamin C. Bromley·Scott J. Kenyon
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Abstract

We consider a scenario where the small satellites of Pluto and Charon grew within a disk of debris from an impact between Charon and a trans-Neptunian Object (TNO). After Charon's orbital motion boosts the debris into a disk-like structure, rapid orbital damping of meter-size or smaller objects is essential to prevent the subsequent re-accretion or dynamical ejection by the binary. From analytical estimates and simulations of disk evolution, we estimate an impactor radius of 30-100 km; smaller (larger) radii apply to an oblique (direct) impact. Although collisions between large TNOs and Charon are unlikely today, they were relatively common within the first 0.1-1 Gyr of the solar system. Compared to models where the small satellites agglomerate in the debris left over by the giant impact that produced the Pluto-Charon binary planet, satellite formation from a later impact on Charon avoids the destabilizing resonances that sweep past the satellites during the early orbital expansion of the binary.

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Benjamin C. Bromley, Scott J. Kenyon. 2020-06-24. A Pluto-Charon Concerto: An Impact on Charon as the Origin of the Small Satellites. https://doi.org/10.3847/1538-3881/ab9e6c

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