Icy Worlds

Early Stages Of Galilean Moon Formation In A Water-depleted Environment

By Keith Cowing
Status Report
January 26, 2023
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Early Stages Of Galilean Moon Formation In A Water-depleted Environment
Io, Europa, Ganymede, and Callisto

A key feature of the Galilean satellite system is its monotonic decrease in bulk density with distance from Jupiter, indicating an ice mass fraction

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.

Olivier Mousis, Antoine Schneeberger, Jonathan I. Lunine, Christopher R. Glein, Alexis Bouquet, Steven D. Vance

Comments: Accepted for publication in The Astrophysical Journal Letters
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2301.10515 [astro-ph.EP] (or arXiv:2301.10515v1 [astro-ph.EP] for this version)
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Submission history
From: Olivier Mousis
[v1] Wed, 25 Jan 2023 10:50:13 UTC (772 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) πŸ––πŸ»