The Galilean Satellites Formed Slowly from Pebbles

Abstract

It is generally accepted that the four major (Galilean) satellites formed out of the gas disk that accompanied Jupiter's formation. However, understanding the specifics of the formation process is challenging as both small particles (pebbles) as well as the satellites are subject to fast migration processes. Here, we hypothesize a new scenario for the origin of the Galilean system, based on the capture of several planetesimal seeds and subsequent slow accretion of pebbles. To halt migration, we invoke an inner disk truncation radius, and other parameters are tuned for the model to match physical, dynamical, compositional, and structural constraints. In our scenario it is natural that Ganymede's mass is determined by pebble isolation. Our slow-pebble-accretion scenario then reproduces the following characteristics: (1) the mass of all the Galilean satellites; (2) the orbits of Io, Europa, and Ganymede captured in mutual 2:1 mean motion resonances; (3) the ice mass fractions of all the Galilean satellites; (4) the unique ice-rock partially differentiated Callisto and the complete differentiation of the other satellites. Our scenario is unique to simultaneously reproduce these disparate properties.

25 pages, 11 figures, 6 tables, accepted for publication in ApJ

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Cited by in corpus (19)

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• Building the Galilean moons system via pebble accretion and migration: A primordial resonant chain
• Circumplanetary disk ices. I. Ice formation vs. viscous evolution and grain drift
• Dynamical history of the Galilean satellites for a fast migration of Callisto
• Photoevaporation of the Jovian circumplanetary disk I. Explaining the orbit of Callisto and the lack of outer regular satellites
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• Effective dust growth in laminar circumplanetary discs with magnetic wind-driven accretion
• The evolution of a circumplanetary disc with a dead zone
• Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. III. Detectability of Giant Exomoons of Wide Separation Giant Planets
• A constraint on the density of Jupiter's moon Thebe from primordial dynamics
• Callisto's Nonresonant Orbit as an Outcome of Circum-Jovian Disk Substructure
• A Validated Low-to-Intermediate Mass Planetary Interior Structure Model and New Mass-Radius Relations
• Not Just Gas: How Solid-Driven Torques Shaped the Migration of the Galilean Moons
• Interpreting ALMA Multiwavelength Continuum Observations of PDS 70 c: An Optically Thick Dust Ring in the Circumplanetary Disk
• The recent crossing of the 7:3 resonance between Ganymede and Callisto
• Formation of Water-rich Giant Planet Satellites at Decretion Disk Ice Lines