The volcanos also produce SO, which is much harder to detect than SO 2. Sulfur dioxide (SO 2) is the main component of Io's atmosphere, coming from sublimation of SO 2 ice, as well as ongoing volcanic eruptions, similar to the production of SO 2 by volcanos on Earth. Because Io is the only volcanically active moon in the solar system - Jupiter's gravitational push and pull heats it up - studies like this give planetary scientists a different perspective than can be obtained by studying volcanos on Earth.įor the first time, the researchers were able to link a volcanic eruption - at Kanehekili Fluctus - to a specific emission line, a so-called "forbidden" line, of the gas sulfur monoxide (SO). In a second paper, accepted for publication in the journal JGR: Planets, a publication of the American Geophysical Union, de Pater and her colleagues report new Webb observations of Io that show several ongoing eruptions, including a brightening at a volcanic complex called Loki Patera and an exceptionally bright eruption at Kanehekili Fluctus. "It helps to actually understand how this so-called radiolysis works and that, indeed, it works as people expected, based on lab experiments on Earth," de Pater said. "These observations of Ganymede provide a key window to understand how such water radiolysis might drive chemistry on icy bodies throughout the outer solar system, including on neighboring Europa and Callisto (the fourth Galilean moon)." "This is likely a really important and widespread process," Trumbo said. On Europa, however, the peroxide was detectable over much of the surface, perhaps, in part, because it has no magnetic field to protect the surface from the fast-moving particles zipping around Jupiter. Trumbo and Michael Brown, professor of planetary astronomy at Caltech, where Trumbo recently received her Ph.D., had earlier studied hydrogen peroxide on Europa, another of Jupiter's four Galilean satellites. "Not only do these particles result in aurorae at Ganymede, as well, but they also impact the icy surface." "Just like how Earth's magnetic field directs charged particles from the sun to the highest latitudes, causing the aurora, Ganymede's magnetic field does the same thing to charged particles from Jupiter's magnetosphere," she added. They suspected that radiolysis would occur primarily around the poles on Ganymede because, unlike all other moons in our solar system, it has a magnetic field that directs charged particles toward the poles. The astronomers argue that the peroxide is produced by charged particles hitting the frozen water ice around the poles and breaking the water molecules into fragments - a process called radiolysis - which then recombine to form H 2O 2. "JWST revealing the presence of hydrogen peroxide at Ganymede's poles shows for the first time that charged particles funneled along Ganymede's magnetic field are preferentially altering the surface chemistry of its polar caps," Trumbo said. Using measurements captured by the near infrared spectrometer (NIRSpec) on JWST, the team detected the absorption of light by hydrogen peroxide - H 2O 2 - around the north and south poles of the moon, a result of charged particles around Jupiter and Ganymede impacting the ice that blankets the moon. Samantha Trumbo, a 51 Pegasi b postdoctoral fellow at Cornell University, led the study of Ganymede, which was published July 21 in the journal Science Advances. De Pater and Thierry Fouchet from the Paris Observatory are co-principal investigators for the Early Release Science solar system observation team, one of 13 teams given early access to the telescope. "This shows that we can do incredible science with the James Webb Space Telescope on solar system objects, even if the object is really very bright, like Jupiter, but also when you look at very faint things next to Jupiter," said Imke de Pater, professor emerita of astronomy and earth and planetary science at the University of California, Berkeley. In two separate publications, astronomers who are part of JWST's Early Release Science program report the first detection of hydrogen peroxide on Ganymede and sulfurous fumes on Io, both the result of Jupiter's domineering influence.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |