Lateral melt variations induce shift in Io’s peak tidal heating

TL;DR

Io's volcanoes are not evenly spread, and this study shows that feedback between tidal heating and interior properties explains the eastward shift in volcanic activity.

Contribution

The study introduces a new mechanism where tidal heating and melt production feedback naturally creates a longitudinal shift in Io’s heating pattern.

Findings

A longitudinal shift in Io’s volcanic activity is explained by feedback between tidal heating and melt production.

This mechanism can also influence the interior evolution of other tidally active celestial bodies.

Radial symmetry in Io’s interior cannot account for the observed volcanic distribution.

Abstract

The innermost Galilean moon, Io, exhibits widespread tidally-driven volcanism. Monitoring of its volcanoes has revealed that they are not homogeneously distributed across its surface: volcanic activity is higher at low latitudes and peaks east of the sub- and anti-Jovian points. Dissipation in a radially symmetric solid body cannot explain the observed longitudinal shift but dissipation in a magma ocean can. However, recent observations show that Io does not have one. Here, we demonstrate that a longitudinal shift in the heating pattern naturally arises from the feedback between tidal heating and melt production. The feedback between tidal dissipation and interior properties that results in interiors that deviate from radial symmetry is expected to drive the interior evolution of other tidally-active worlds, including icy moons such as Europa and Enceladus and exo-planets/moons with high eccentricity or obliquity.

Io’s distribution of volcanoes shows an eastward shift not explained by existing tidal heating models. Here, the authors show that feedback between tidal heating and interior properties naturally forms a heating pattern with a longitudinal shift.

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