Year: 2020
Type: article
Abstract: 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.
Institutions: University of California, Santa Cruz, University of Arizona
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3021993583