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Waves surge in opposite directions around Io's largest lava lake

Best ever images of a lava lake on Jupiter's innermost large moon reveal its surface regenerating itself, sometimes clockwise and sometimes anticlockwise 
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Jupiter's Moon Io
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Long-Term, Hi-Res Tracking of Eruptions on Jupiter's Moon Io

Jupiter's moon Io continues to be the most volcanically active body in the solar system, as documented by the longest series of frequent, high-resolution observations of the moon's thermal emission ever obtained.
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Underground Magma Ocean Could Explain Io's 'Misplaced' Volcanoes

Tides flowing in a subsurface ocean of molten rock, or magma, could explain why Jupiter's moon Io appears to have its volcanoes in the "wrong" place. New NASA research implies that oceans beneath the crusts of tidally stressed moons may be more common and last longer than expected. The phenomenon applies to oceans made from either magma or water, potentially increasing the odds for life elsewhere in the universe.
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Massive Volcano Erupts on Jupiter's Moon, Io

Jupiters moon Io is the most volcanic body in the solar system, and astronomers recently witnessed an eruption bigger than any ever recorded on Earth.
Dr. Imke de Pater, professor of astronomy and planetary science at the University of California in Berkeley spotted the eruption on August 15, using the Keck II telescope on Mauna Kea in Hawaii.

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Huge lava fountains seen gushing from Jupiter moon

One of the most massive volcanic eruptions in the solar system has been spotted on Jupiter's moon Io - by a telescope perched on a volcano on Earth.
On 15 August the Keck II telescope on Mauna Kea in Hawaii recorded fountains of lava gushing from fissures in the Rarog Patera region of Io.



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Eruption of Surt, 1979
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Surt is an active volcano on Jupiter's moon Io.

The first eruption observed by Earth-based astronomers following the discovery of Ionian volcanism took place at Surt on June 11, 1979
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Io plasma torus
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Title: Cassini UVIS observations of the Io plasma torus. II. Radial variations
Authors: Andrew J. Steffl, Fran Bagenal, A. Ian F. Stewart

On January 14, 2001, shortly after the Cassini spacecraft's closest approach to Jupiter, the Ultraviolet Imaging Spectrometer (UVIS) made a radial scan through the midnight sector of Io plasma torus. The Io torus has not been previously observed at this local time. The UVIS data consist of 2-D spectrally dispersed images of the Io plasma torus in the wavelength range of 561{\AA}-1912{\AA}. We developed a spectral emissions model that incorporates the latest atomic physics data contained in the CHIANTI database in order to derive the composition of the torus plasma as a function of radial distance. Electron temperatures derived from the UVIS torus spectra are generally less than those observed during the Voyager era. We find the torus ion composition derived from the UVIS spectra to be significantly different from the composition during the Voyager era. Notably, the torus contains substantially less oxygen, with a total oxygen-to-sulfur ion ratio of 0.9. The average ion charge state has increased to 1.7. We detect S V in the Io torus at the 3{\sigma} level. S V has a mixing ratio of 0.5%. The spectral emission model used in can approximate the effects of a non-thermal distribution of electrons. The ion composition derived using a kappa distribution of electrons is identical to that derived using a Maxwellian electron distribution; however, the kappa distribution model requires a higher electron column density to match the observed brightness of the spectra. The derived value of the kappa parameter decreases with radial distance and is consistent with the value of {\kappa}=2.4 at 8 RJ derived by the Ulysses URAP instrument (Meyer-Vernet et al., 1995). The observed radial profile of electron column density is consistent with a flux tube content, NL^2, that is proportional to r^-2.

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Anniversary of the Galileo spacecraft's Io flyby in 2002.

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Title: Discovery of Volcanic Activity on Io. A Historical Review
Authors: L. A. Morabito (1) ((1) Victor Valley College, Victorville, CA, USA)

In the 2 March 1979 issue of Science 203 S. J. Peale, P. Cassen and R. T. Reynolds published their paper "Melting of Io by tidal dissipation" indicating "the dissipation of tidal energy in Jupiter's moon Io is likely to have melted a major fraction of the mass." The conclusion of their paper was that "consequences of a largely molten interior may be evident in pictures of Io's surface returned by Voyager 1." Just three days after that, the Voyager 1 spacecraft would pass within 0.3 Jupiter radii of Io. The Jet Propulsion Laboratory navigation team's orbit estimation program as well as the team members themselves performed flawlessly. In regards to the optical navigation component image extraction of satellite centers in Voyager pictures taken for optical navigation at Jupiter rms post fit residuals were less than 0.25 pixels. The cognizant engineer of the Optical Navigation Image Processing System was astronomer Linda Morabito. Four days after the Voyager 1 encounter with Jupiter, after performing image processing on a picture of Io taken by the spacecraft the day before, something anomalous emerged off the limb of Io. This historical review written by the discoverer recounts her minute-by-minute quest to identify what was a volcanic plume, the first evidence of active volcanism seen beyond Earth. Many ingredients of the account reflect historic themes in the process of scientific discovery.

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Io's fiery show monitored with adaptive optics

Watching active volcanic eruptions should be done from a safe distance, and a group of California researchers has figured out how to do it from, ironically, Mauna Kea - one of Earth's tallest volcanoes - using the W. M. Keck Observatory. Employing an ingenious combination of telescopic surveys and archival data, they have gathered nearly 40 distinct snapshots of effusive (slow) volcanic eruptions and high temperature outbursts on Jupiter's tiny moon, Io, showing details as small as 100 km on the moon's surface.
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