Inclination damping on Callisto
Abstract
Callisto is thought to possess a subsurface ocean, which will dissipate energy due to obliquity tides. This dissipation should have damped any primordial inclination within 1 Gyr - and yet Callisto retains a present-day inclination. We argue that Callisto's inclination and eccentricity were both excited in the relatively recent past (~0.3 Gyr). This excitation occurred as Callisto migrated outwards according to the "resonance-locking" model and passed through a 2:1 mean-motion resonance with Ganymede. Ganymede's orbital elements were likewise excited by the same event. To explain the present-day orbital elements we deduce a solid-body tidal k2/Q~0.05 for Callisto and a significantly lower value for Ganymede.
Cite
@article{arxiv.2009.05002,
title = {Inclination damping on Callisto},
author = {Brynna G. Downey and Francis Nimmo and Isamu Matsuyama},
journal= {arXiv preprint arXiv:2009.05002},
year = {2020}
}
Comments
12 pages, 9 figures, accepted in MNRAS