Observations of Io, Jupiter’s volcanic moon, reveal near-annual outbursts, but this is by far the largest observed to date. What could this new eruption tell us?
The most active object in the solar system
The surface of Io, unlike that of Europa or Ganymede, is covered in lava lakes formed from hundreds of volcanoes scattered across the surface. Some of these eruptions even rise to several tens of kilometers in height. We owe this activity to the gravity of jupiter which, combined with that of two other Jovian moons – Europa and Ganymede -, creates powerful tidal forces that stretch and compress Iowhich is the innermost of the four major moons in this system.
An observatory located in Arizona, managed by Planetary Science Institute (PSI), has been analyzing volcanic activity on Io for just over five years. The observations are made thanks to a coronagraph able to attenuate the light coming from Jupiter, thus allowing the imaging of weak gases near the planet. Significant brightening of two of these gases, ionized sodium and sulfurstarted between July and September 2022, until last December.
The observations were made by astronomer Jeff Morgenthaler, who operated the observatory.
In these images, the sodium appeared surprisingly bright compared to previous observations. Conversely, the ionized sulfur, which forms a donut-like structure encircling Jupiter (called the Io plasma torus), was oddly not as bright as usual. ” This could tell us something about the composition of the volcanic activity that produced the eruption« , note the astronomer. ” It could also suggest that the torus is more efficient at getting rid of matter when more matter is thrown into it.« .
Juno approaching
These observations have implications for the Juno mission. After approaching Ganymede and D’Europe several months ago, the American probe is gradually approaching Io for a close flyby scheduled for December 2023. However, several of its instruments will be sensitive to changes in the plasma environment around Io and Jupiter. These future observations could thus tell us if this volcanic explosion had a different composition from the previous ones.
In the meantime, before Juno can get close enough, the astronomer hopes more observations can be made. For this work, the researcher relied on a relatively simple telescope (IoIO) configured to be controlled remotely. Almost all the parts used to build it are available in specialist stores. These additional small instruments, scattered around the world, could help astronomers continue to monitor the Jovian moon from Earth during interruptions imposed by adverse weather conditions.