Gemini North and W.M. Keck images of Io at different near-infrared wavelengths; the name of the filter is indicated in the black box at the start of each section. The bright spots are thermal emissions from Io’s myriad volcanoes. Note the increasing number of hot spots detected at longer wavelengths, i.e. towards the bottom of the figure. Credit: Katherine de Kleer and Imke de Pater, UC Berkeley/Gemini Observatory/AURA/W.M. Keck Observatory
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All hot spot detections from August 2013 through December 2015 shown on a full map of Io. Each circle represents a new detection; the size of the circle corresponds logarithmically to the intensity, and more opaque regions are where a hot spot was detected multiple times. The color and symbol indicate the type of eruption, following the legend. Loki Patera is at 310 West, 10 North and Kurdalagon Patera is at 220 West, 50 South. Credit: Katherine de Kleer and Imke de Pater, UC Berkeley
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Jupiter’s moon Io is the most volcanically active world in our Solar System. Now, the longest series of frequent high-resolution tracking of Io’s thermal emission is providing insights on Io’s volcanoes thanks to a powerful joint observation program between the Gemini North telescope (with NIRI+Altair instrument) and the W.M. Keck Observatory.
The observations use advanced adaptive optics technology to remove distortions caused by the Earth’s atmosphere and provide remarkably sharp imaging of Io’s volcanic activity over a period of 29 months. The results show patterns in the volcanic activity over time and location on the satellite, but also present many new questions.
Compellingly, some of the eruptions appeared to progress across the surface over time, as if one somehow triggered another 500 kilometers away. According to University of California Berkeley (UCB) Graduate Student Katherine de Kleer, "While it stretches the imagination to devise a mechanism that could operate over distances of 500 kilometers, Io’s volcanism is far more extreme than anything we have on Earth and continues to amaze and baffle us.” De Kleer led the analysis of the data for this study.
“These remarkable images illustrate the great strides that have been made in high-resolution imaging from the ground over the past decade,” notes Chris Davis, Program Director for the Gemini Observatory at the National Science Foundation, which contributes the bulk of the operations costs of the observatory. “It is amazing to think that, with adaptive optics on 8-10 meter class telescopes like Gemini and Keck, we are now able to resolve features on the surfaces of not just neighboring planets, but their moons as well!”
The results were presented at the American Astronomical Society’s Division of Planetary Sciences and the European Planetary Sciences Congress in Pasadena, California on Thursday, October 20, 2016. De Kleer, and her advisor at UCB, Imke de Pater, presented the results jointly based on a pair of papers accepted for publication in the journal Icarus.
The full UCB press release, images, and resources on this work is available here.