Early stages of Galilean moon formation in a water-depleted environment

Abstract

A key feature of the Galilean satellite system is its monotonic decrease in bulk density with distance from Jupiter, indicating an ice mass fraction that is zero in the innermost moon Io, and about half in the outer moons Ganymede and Callisto. Jupiter formation models, and perhaps the Juno spacecraft water measurements, are consistent with the possibility that the Jovian system may have formed, at least partly, from ice-poor material. And yet, models of the formation of the Galilean satellites usually assume abundant water ice in the system. Here, we investigate the possibility that the Jovian circumplanetary disk was populated with ice-depleted chondritic minerals, including phyllosilicates. We show that the dehydration of such particles and the outward diffusion of the released water vapor allow condensation of significant amounts of ice in the formation region of Ganymede and Callisto in the Jovian circumplanetary disk. Our model predicts that Europa, Ganymede and Callisto should have accreted little if any volatiles other than water ice, in contrast to the comet-like composition of Saturn's moon Enceladus. This mechanism allows for the presence of ice-rich moons in water-depleted formation environments around exoplanets as well.

arXiv commentAccepted for publication in The Astrophysical Journal Letters

References in corpus (19)

• A simple model for the evolution of the dust population in protoplanetary disks
• Distribution of Accreting Gas and Angular Momentum onto Circumplanetary Disks
• Origin of the Different Architectures of the Jovian and Saturnian Satellite Systems
• The water abundance in Jupiter's equatorial zone
• Jupiter's composition suggests its core assembled exterior to the N2 snowline
• A Primordial Origin of the Laplace Relation Among the Galilean Satellites
• How drifting and evaporating pebbles shape giant planets II: Volatiles and refractories in atmospheres
• Volatile snowlines in embedded disks around low-mass protostars
• Revelations on Jupiter's Formation, Evolution and Interior: Challenges from Juno Results
• Carbon-rich planet formation in a solar composition disk
• Effects of the Planetary Temperature on the Circumplanetary Disk and on the Gap
• Double-diffusive erosion of the core of Jupiter
• On the volatile enrichments and composition of Jupiter
• Pebble accretion at the origin of water in Europa
• Building the Galilean moons system via pebble accretion and migration: A primordial resonant chain
• Constraints from deuterium on the formation of icy bodies in the Jovian system and beyond
• Enrichment of Jupiter's atmosphere by late planetesimal bombardment
• The nature and composition of Jupiter's building blocks derived from the water abundance measurements by the Juno spacecraft
• Photoevaporation of the Jovian circumplanetary disk I. Explaining the orbit of Callisto and the lack of outer regular satellites

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