Widespread occurrence of lava lakes on Io observed from Juno

TL;DR

This study reports widespread lava lakes on Io observed by Juno's JIRAM instrument, revealing their ubiquity, size, crust thickness, and new active hotspots, enhancing understanding of Io's volcanic activity.

Contribution

It provides the first extensive observational evidence of lava lakes on Io, including new active hotspots and detailed measurements of their properties.

Findings

Over 40 lava lakes identified on Io.

Lava lakes are present in more than 50% of paterae.

Crust thickness of lava lakes estimated at 5-10 meters.

Abstract

We report recent observations of lava lakes within patera on Io made by the JIRAM imager/spectrometer on board the Juno spacecraft, taken during close observation occurred in the extended mission. At least 40 lava lakes have been identified from JIRAM observations. The majority (>50%) of paterae have elevated thermal signatures when imaged at sufficiently high spatial resolution (a few km/pixel), implying that lava lakes are ubiquitous on Io. The annular width of the spattering region around the margins, a characteristic of lava lakes, is of the order of few meters to tens of meters, the diameter of the observed lava lakes ranges from 10 to 100 km. The thickness of the crust in the center of some lava lakes is of the order of 5-10 m; we estimate that this crust is a few years old. Also, the bulk of the thermal emission comes from the much larger crust and not from the smaller exposed lava, so the total power output cannot be calculated from the 5-um radiance alone. Eight of the proposed lava lakes have never been reported previously as active hotspots.