München 2019 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 8: Planets and Exoplanets
EP 8.3: Vortrag
Donnerstag, 21. März 2019, 15:00–15:15, HS 9
Mapping the Brightness of Ganymede’s UV Aurora using HST STIS Observations — •Alexander Marzok1, Joachim Saur1, Denis Grodent2, and Lorenz Roth3 — 1University of Cologne, Institute for Geophysics and Meteorology — 2University of Liège, Institute for Astrophysics and Geophysics — 3KTH Institute of Technology, Department of Space and Plasma Physics
Ganymede is the only known moon in the solar system with an intrinsic magnetic field and two auroral ovals around its magnetic north and south poles. In this work we analyze Hubble Space Telescope (HST) observations of Ganymede at OI 1356 Å to study the structure of its auroral ovals. Our aim is to combine HST observations from various epochs to generate a brightness map of Ganymede’s two auroral ovals. Charged particles from Jupiter’s magnetosphere can not excite the brightest emissions of 300 R only from the reported electron temperatures, but need to be accelerated due to magnetic reconnection happening between the magnetic field lines of Jupiter and Ganymede. The sub-alfvénic speed of the charged particles makes the Ganymede system different compared to the planets in the solar wind because no bow shock is formed, resulting in a non-turbulent environment that is ideal to study the phenomenon. Our created map is intended to serve as a diagnostic tool helping to investigate the process of magnetic reconnection responsible for the emissions and structure of the aurora.