SMuK 2023 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 4: Planetary atmospheres
EP 4.1: Vortrag
Dienstag, 21. März 2023, 18:00–18:15, ZEU/0160
Jupiter moon Ganymede's atmosphere observed with the Hubble Space Telescope — •Lorenz Roth1, Gregorio Marchesini1, Tracy Becker2, Jens Hoeijmakers3, Philippa Molyneux2, Kurt Retherford2, Joachim Saur4, Shane Carberry Mogan5, and Jamey Szalay6 — 1KTH Royal Institute of Technology, Stockholm Sweden / ESO Garching bei München — 2Southwest Research Institute, San Antonio, TX, USA — 3Lund University, Sweden — 4Universität zu Köln — 5University of California, Berkeley, CA, USA — 6Princeton University, Princeton, NJ, USA
Jupiter's moon Ganymede is the largest moon in the Solar System and the only one that generates its own magnetic field in the interior. Ganymede also possesses a tenuous water-based atmosphere, produced by the solar and Jovian plasma irradiation of its icy surface. Here we report results from far-ultraviolet observations by the Hubble Space Telescope of Ganymede transiting across the planet's dayside hemisphere. Within a targeted campaign on 9 September 2021 two exposures were taken during one transit passage to probe for attenuation of Jupiter's hydrogen Lyman-α dayglow above the moon limb. The background dayglow is slightly attenuated over an extended region around Ganymede. The obtained vertical H column densities are consistent with previous results. Constraining angular variability around Ganymede's disk, we derive an upper limit on a local H2O column density such as could arise from outgassing plumes in regions near the observed moon limb.