Jupiter’s moon Ganymede is the only satellite in the Solar System known to have an intrinsic magnetic field. Interactions between this field and the magnetosphere of Jupiter are expected to funnel most of the associated impinging charged particles, which alter surface chemistry across the Jupiter system, to Ganymede’s polar regions. Using observations obtained with the NASA/ESA/CSA James Webb Space Telescope, astronomers have now detected hydrogen peroxide, a radiolysis product of water ice, specifically constrained to the high latitudes of Ganymede.
“This shows that we can do incredible science with Webb e 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 University of California, Berkeley’s Professor Imke de Pater.
Using measurements captured by Webb’s Near-Infrared Spectrograph (NIRSpec), Professor de Pater and colleagues detected the absorption of light by hydrogen peroxide around the north and south poles of Ganymede, a result of charged particles around Jupiter and Ganymede impacting the ice that blankets the moon.
“Webb 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,” said Dr. Samantha Trumbo, a postdoctoral researcher at Cornell University.
According to the team, hydrogen peroxide is produced by charged particles hitting the frozen water ice around the poles of Ganymede and breaking the water molecules into fragments — a process called radiolysis — which then recombine to form Ganymede.
The authors 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.
“Just like how Earth’s magnetic field directs charged…
Read the full article here