Bremen 2017 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 10: Planeten und kleine Körper I

EP 10.1: Hauptvortrag

Donnerstag, 16. März 2017, 08:30–09:00, GW2 B2880

Sounding the interior of Jupiter's moons through observations of their atmospheric emissions — •Lorenz Roth — KTH Royal Institute of Technology, Stockholm, Sweden

Magnetic field measurements by the Galileo spacecraft were used to probe the subsurface water oceans on Jupiter's moons Europa and Callisto through electromagnetic induction. In addition to in-situ spacecraft measurements, electromagnetic induction at Jupiter's moons can also be investigated through observations of auroral emission from the tenuous moon atmospheres. This is possible, because the morphology of the aurora, excited by the interaction of magnetospheric plasma with the atmospheres, is controlled by the magnetic field. In the case of Ganymede, magnetic fields induced in the subsurface ocean effectively suppress oscillations of the moon's auroral ovals, which was observed by the Hubble Space Telescope (HST). Magnetic induction in Europa's ocean might similarly affect its auroral emissions, but the effects could not be measured or determined yet, although the aurora has been extensively studied by HST. Observations of strongly oscillating auroral spots at the volcanic moon Io contradict the existence of a conductive magma ocean, postulated earlier based on in-situ measurements. I present an overview on our groups recent work on the aurora observations of Jupiter's moons Io, Europa and Ganymede and their interpretation with respect to electromagnetic induction inside the moons.