| Issue |
A&A
Volume 706, February 2026
|
|
|---|---|---|
| Article Number | L7 | |
| Number of page(s) | 5 | |
| Section | Letters to the Editor | |
| DOI | https://doi.org/10.1051/0004-6361/202558173 | |
| Published online | 30 January 2026 | |
Letter to the Editor
Not just gas: How solids-driven torques shaped the migration of the Galilean moons
1
Departamento de Astronomía, Facultad de Ciencias Físicas y Matemáticas Universidad de Concepción Av. Esteban Iturra s/n Barrio Universitario Casilla 160-C Concepción, Chile
2
Department of Astronomy and Steward Observatory, University of Arizona Tucson Arizona 85721, USA
3
Centro Multidisciplinario de Física, Vicerrectoría de Investigación, Universidad Mayor 8580745 Santiago, Chile
4
Facultad de Ingeniería y Ciencias Universidad Adolfo Ibáñez Av. Diagonal las Torres 2640 Peñalolén, Chile
★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
19
November
2025
Accepted:
6
January
2026
Context. A crucial aspect of formation models for the Galilean moons of Jupiter is that the objects survive rapid inward orbital migration.
Aims. The primary aim of this study is to investigate the orbital migration of the Galilean moons by incorporating self-consistent solid dynamics in models of circumjovian disks.
Methods. We performed two-fluid simulations using the code FARGO3D on a 2D polar grid. The simulations modeled a satellite with the mass of a protomoon, Europa, or Ganymede that interacts with a circumjovian disk. The dust component, coupled to the gas via a drag force, was characterized by the dust-to-gas mass ratio (ϵ) and the Stokes number (Ts).
Results. The effect of solids fundamentally alters the evolution of the satellites. We identified a vast parameter space in which migration is slowed, halted, robustly reversed (leading to outward migration), or significantly accelerated inward. The migration rate is dependent on satellite mass. This provides a natural source of differential migration.
Conclusions. Solid dynamics provides a robust and self-consistent mechanism that fundamentally alters the migration of the Galilean moons. This might address the long-standing migration catastrophe. This mechanism critically affects the survival of satellites and might offer a viable physical process to explain the establishment of resonances through differential migration. These findings establish that solid torques are a critical non-negligible factor in the shaping of the final architecture of satellite systems.
Key words: planets and satellites: formation
© The Authors 2026
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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