New Radio Pictures from Atacama Large mm / m Array (Alma) They appear for the first time the direct impact of volcanic activity on its atmosphere JupiterMoon Io.
Io is the most volcanically active moon in our solar system. Hosting more than 400 active volcanoes, it spews sulfur gases that give Io their yellow, white, orange, and red colors when it freezes on its surface.
Although it is extremely thin – a billion times thinner than Earth’s atmosphere – Io has an atmosphere that can inform us about Io’s volcanic activity and provide us with a window into the strange interior of the moon and what is happening under its colorful crust.
Previous research has shown that the ion’s atmosphere is dominated by sulfur dioxide, which ultimately comes from volcanic activity. “However, no process is known to drive the dynamics of Io’s atmosphere,” said Imke de Pater of University of California, Berkeley. “Is it volcanic activity, or is it a gas that has risen (moved from a solid state to a gaseous state) from the ice surface when Io is in sunlight?”
To distinguish between the different processes that give rise to Io’s atmosphere, a team of astronomers used ALMA to make snapshots of the moon as it passes in and out of Jupiter’s shadow (they call this an “eclipse”).
This video shows images of Jupiter’s moon Io in radio (made with ALMA), and an optical light (made by the Voyager 1 and Galileo missions). ALMA images were taken as Io passed into the shadow of Jupiter in March 2018 (eclipse), and from Jupiter’s shadow to sunlight in September 2018. These wireless images for the first time show plumes of sulfur dioxide (in yellow) rising from volcanoes on Io. Credit: ALMA (This/ NAOJ / NRAO) ID Bater et al.; NRAO / AUI NSF, S. Dagnello; NASA
“When Io passes in the shadow of Jupiter, and is out of direct sunlight, it is very cold for sulfur dioxide gas, and it condenses on the surface of Io. During that time, we can only see sulfur dioxide from volcanic sources. So we can see exactly How much the atmosphere is affected by volcanic activity, ”explained Statia Luszcz-Cook from Columbia University, New York.
Thanks to the remarkable accuracy and sensitivity of ALMA, astronomers were, for the first time, able to see plumes of sulfur dioxide (SO2) and sulfur monoxide (SO) rising from volcanoes. Based on the snapshots, they calculated that active volcanoes directly produce 30-50 percent of Io’s atmosphere.
The ALMA images also showed a third gas emerging from volcanoes: potassium chloride (KCl). “We see KCl in volcanic regions where we don’t see SO2 or SO2,” Luszcz-Cook said. “This is strong evidence that magma reservoirs differ for different volcanoes.”
Io is volcanically active due to a process called tidal heating. Io orbits Jupiter in a completely non-circular orbit, and just as the Moon always faces the same side of Earth, so the same side of Io always faces Jupiter. The gravitational pull of Jupiter’s other moons, Europa and Ganymede, is causing massive amounts of internal friction and heat, giving rise to volcanoes such as Loki Patera, which span more than 200 kilometers (124 miles). Luszcz-Cook added: “By studying the atmosphere of Io and volcanic activity, we learn more not only about the volcanoes themselves, but also about the process of tidal heating and the interior Io.”
The temperature remains unknown in Io’s lower atmosphere. In future research, astronomers hope to measure this with ALMA. “To measure the temperature of Io’s atmosphere, we need to have a higher resolution in our observations, which requires us to observe the moon for a longer period of time. We can only do this when Io is in sunlight because it does not spend much time in the eclipse,” he said De pater. “During this observation, Io will rotate by tens of degrees. We will need to implement a software that helps us make unstained images. We did this previously using radio images of Jupiter made with ALMA and Very large array (VLA). “
The reference: “ALMA Notes on Io’s Entry into and Exit from the Eclipse” by Emky de Pater, Statia Lochs-Cook, Patricio Rojo, Erin Redwing, Catherine de Claire and Ariel Mollet, 21 October 2020, The Journal of Planetary Sciences.
DOI: 10.3847 / PSJ / abb93d
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