A team of astronomers recently captured new images of a volcanic plume on Io, Jupiter’s moon, during the 17th flight of the giant by the Juno spacecraft.
Io is not very welcoming. Close to Jupiter – the fourth largest satellite of the Solar System – the moon is characterized by intense volcanic and magmatic activity. In fact, these new observations bear witness to this. On December 21st, the Juno probe, in the Jovian system since 2016, focused on the moon for over an hour, allowing astronomers to observe the polar regions. They then fell on a volcanic eruption, betrayed by the evaporation of a plume on the surface.
“No one expected us to have the chance to see an active volcanic plume shot on the surface of the moon,” said Scott Bolton, Mission Manager. “It’s a real New Year’s gift that shows us that Juno has the ability to see plumes clearly. ”
JunoCam was able to photograph this image a few minutes before Io (3630 km in diameter) entered the shadow of Jupiter. “The ground is already darkened, but the height of the plume allows it to reflect the sun’s light, much like the mountain tops or clouds on the Earth after sunset,” says the head of the JunoCam Candice Hansen-Koharcheck.
The scene, reconstructed from images of red, blue and green filters, was photographed December 21, 2018 (around 12 pm). The Juno probe was about 300,000 km from Io, the volcanic moon of Jupiter. Credits: NASA / SwRI / MSSS
“Although the moons of Jupiter are not JIRAM’s main objectives, whenever we pass close to one of them, we take the opportunity to make an observation,” says Alberto Adriani of the Italian National Institute of Astrophysics. The instrument is sensitive to infrared wavelengths, which is perfect for studying Io volcanism. This is one of the best images of Io collected so far.
These new images will allow astronomers to better understand the interactions of the gas giant with its nearest moon (421 600 kilometers separate them). The Io volcanoes, which emit plumes of sulfur dioxide, were discovered by the Voyager 1 spac ecraft, which flew by it in 1979. They are the result of a strong gravitational interaction of the moon with Jupiter. Io is also considered as the most active object of the solar system.