Sulfur and chlorine isotopes in Io’s atmosphere indicate that Io has been volcanically active throughout the solar system’s 4.57 billion-year history.
This global map of Io was obtained in January 1999 by NASA’s Galileo spacecraft. Image credit: NASA/JPL/University of Arizona.
Jupiter’s moon Io is the most volcanically active body in the solar system.
Io’s volcanic activity is the result of tidal heating due to friction that occurs within the moon’s interior as it is pulled between Jupiter and its neighboring moons Europa and Ganymede.
However, it is not fully understood how long this moon has hosted such extensive volcanic activity.
Due to the Moon’s current level of volcanic activity, Io’s surface is constantly being reworked, leaving only the most recent 1 million years of its geological record.
Stable isotope measurements of volatile elements in Io’s atmosphere could provide information about Io’s volcanic history.
“Io is a moon of Jupiter and is the most volcanically active body in the solar system,” says Dr. Ellie Hughes, a volcanic fluid geochemist at GNS Science.
“Io is in orbital resonance with Jupiter’s other two large moons, Europa and Ganymede.”
“For every time Ganymede orbits Jupiter once, Europa orbits twice and Io orbits four times.”
“This configuration causes Io’s orbit around Jupiter to be elliptical rather than circular, causing Jupiter’s gravity on Io to change periodically.”
“This change in gravity causes something called tidal heating on Io, just as the moon causes ocean tides on Earth, which causes volcanic activity.”
“However, it is unclear whether volcanic activity has occurred on Io over a long period of time or how this activity has changed over Io’s 4.57 billion year history.”
“Io has experienced so much volcanic activity that its surface is constantly being updated, leaving little trace of its past.”
“Fortunately, we can study Io back in time by studying sulfur and its isotopes.”
In the new study, Hughes, Caltech researcher Catherine de Clare, and colleagues used the Atacama Large Millimeter/Submillimeter Array (ALMA) to observe gases in Io’s tenuous atmosphere. , we measured stable isotope radio waves of sulfur and chlorine. Carries molecules.
Scientists believe that both elements have lower concentrations of heavier isotopes compared to the solar system average due to the loss of lighter isotopes from the upper atmosphere as material is continually recycled between Io’s interior and atmosphere. I discovered that it is very plentiful.
The findings show that Io lost 94% to 99% of its sulfur through this outgassing and recycling process.
This would require that Io maintained its current level of volcanic activity throughout its lifetime.
“Sulfur is released into the atmosphere from Io’s interior by tidal heating from volcanic activity,” Hughes said.
“Some of the sulfur is lost to space by Jupiter’s magnetosphere, a bundle of charged particles swirling around Jupiter that continuously bombards Io’s atmosphere.”
“The sulfur that is left behind will eventually be buried back inside Io, ready to start the cycle again.”
“Isotopes of the same element have different weights from each other, so they can behave slightly differently during this cycle.”
“We found that the sulfur lost to space on Io is a little lighter isotopically than the sulfur that is recycled into Io’s interior.”
“Thus, over time, the sulfur left on Io becomes isotopically heavier and heavier. How heavy it gets depends on how long the volcanic activity has been occurring.”
“We found much more isotopically heavy sulfur in Io’s atmosphere than the solar system average. This requires that Io has lost almost all of its original sulfur.”
“Based on numerical modeling, this means that Io has been volcanically active for billions of years, and that tidal heating and orbital resonance have also occurred for most of Io’s history.”
“In the future, variability in atmospheric sulfur isotopic composition may help quantify Io’s average tidal heating rate.”
of study appear in the diary science.
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katherine de clair other. Isotopic evidence for long-lived volcanism on Io. science, published online on April 18, 2024. doi: 10.1126/science.adj0625
Source: www.sci.news
