* Astronomy

Blobrana · L

RE: Io

Blobrana · L

Mapping Volcanic Heat on Io

A new study finds that the pattern of heat coming from volcanoes on Io's surface disposes of the generally-accepted model of internal heating. The heat pouring out of Io's hundreds of erupting volcanoes indicates a complex, multi-layer source. These results come from data collected by NASA spacecraft and ground-based telescopes and appear in the June issue of the journal Icarus.
A map of hot spots, classified by the amount of heat being emitted, shows the global distribution and wide range of volcanic activity on Io. Most of Io's eruptions dwarf their contemporaries on Earth.
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Blobrana · L

Title: The rotation of Io predicted by the Poincaré-Hough model
Authors: Benoît Noyelles

This paper proposes to study the rotation of the Galilean satellite of Jupiter Io, in considering core-mantle coupling. This satellite is particularly interesting because it experiences strong tidal dissipation inducing a very active surface. Moreover, the flow of the fluid inside its core is reputed to be unstable.
We first elaborate 10 different models of the interior of Io, considering either a Fe or a FeS core, using measured values of the gravity coefficients J2 and C22, before studying their response to the 4-degrees of freedom Poincare-Hough model. The study requires numerical methods like integration of ODE and frequency analysis of the solutions. We then study the stability of the flow of the fluid.
We show that these different models have a quite small influence on the longitudinal librations and the equilibrium obliquity, with amplitude of about 30 and 8 seconds of arc respectively, because of the relatively small inertia of the core. However, sulphur in the core can pump the tilt of the velocity field constituting the core. Moreover, in all our models the flow in unstable with a growth time of about 1,000 years for a Fe core and 5,000 years for a FeS one.

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Blobrana · L

First Geologic Map of Jupiter's Moon Io Details an Otherworldly Volcanic Surface

More than 400 years after its discovery by Galileo, the innermost large moon of Jupiter - Io - can finally rest on its geologic laurels. A group of scientists led by Dr. David A. Williams of Arizona State University has produced the first global geologic map of the Jovian satellite. The map, which was published by the U. S. Geological Survey, technically illustrates the geologic character of some of the most unique and active volcanoes ever documented in the solar system.
The Io geologic map is unique from other USGS-published planetary geologic maps because surface features were characterised using four distinct global image mosaics. Produced by the USGS, these image mosaics combine the best images from NASA's Voyager 1 and 2 missions (acquired in 1979) as well as the Galileo orbiter (1995-2003).
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Voyager 1 Flyby of Io

Spoiler

Spoiler

Voyager 1 flew past the Io on March 5, 1979 from a distance of 20,600 km. The images returned during the approach revealed a strange, multi-coloured landscape devoid of impact craters. The highest-resolution images showed a relatively young surface punctuated by oddly shaped pits, mountains taller than Mount Everest, and features resembling volcanic lava flows.
Shortly after the encounter, Voyager navigation engineer Linda A. Morabito noticed a plume emanating from the surface in one of the images.
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Blobrana · L

Jupiter moon 'holds magma ocean'

Io is the most volcanic world in the Solar System and scientists think they now have a better idea of why that is.
The moon of Jupiter erupts about 100 times more lava on to its surface each year than does Earth.
A re-assessment of data from Nasa's Galileo probe suggests all this activity is being fed from a giant magma ocean under Io's crust.
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Blobrana · L

Galileo Data Reveal Magma Ocean Under Jupiter Moon

New data analysis from NASA's Galileo spacecraft reveals a subsurface ocean of molten or partially molten magma beneath the surface of Jupiter's volcanic moon Io.
The finding heralds the first direct confirmation of this kind of magma layer at Io and explains why the moon is the most volcanic object known in the solar system. The research was conducted by scientists at the University of California, Los Angeles; the University of California, Santa Cruz;, and the University of Michigan, Ann Arbor. The study is published this week in the journal Science.
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Blobrana · L

Jupiter's Volcanic Moon Io Could be Target for Life

When it comes to where extraterrestrial life might dwell in our own solar system, Jupiter's moon Europa often grabs the spotlight. However, its extraordinarily volcanic sibling Io might be a possible habitat as well.
A bit larger than Earth's moon, Io is the innermost of Jupiter's large satellites and the most volcanically active body in the solar system, with plumes of matter rising up to 186 miles (300 km) above the surface.
This extreme activity is the result of Jupiter's powerful gravitational pull, which causes Io's tormented solid crust to bulge up and down 328 feet (100 meters) or more, generating intense heat in Io due to friction. Although the heat near the volcanoes can reach some 3000 degrees F (1649 degrees C), high enough to keep lava liquid, Io's surface temperature averages at about negative 202 degrees F (-130 degrees C), leading to sulphur dioxide snowfields.
This means Io is a land of both fire and ice.
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Blobrana · L

The Chemical Composition of Io

From the comments on the 2009 Autumn AGU meeting abstracts post back in October, I think it might be useful to have an overview post on what is known about Io's composition and the volatile chemistry that takes place at Io's volcanoes and in its atmosphere. Much of the information I will present here is based on models of the kinds of chemical reactions that are thought to occur, but a few key measurements do underlie this discussion. This first is Io's bulk density, derived from measurements of Io's size and Io's effect on passing spacecraft and its fellow Jovian satellites. The latter measurement allows for an estimate of Io's mass. Second, spectroscopic measurements of Io's surface and atmosphere provide details on the sulphurous volatiles that are common at Io's volcanoes and cover the bulk of Io's surface. Finally, in situ and spectroscopic measurements of the composition of the Io Plasma Torus, a belt of charged particles co-orbital with Io, provide hints to the atomic breakdown of compounds that escape from Io and its atmosphere.
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Blobrana · L

Tohil Mons Rising

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