Stuttgart 2012 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 5: Planeten und kleine Körper I
EP 5.6: Vortrag
Mittwoch, 14. März 2012, 15:15–15:30, V55.02
Variations of the Aurora at Jupiter's moon Io — •Lorenz Roth1, Joachim Saur1, Paul Feldman2, Darrell Strobel2 und Kurt Retherford3 — 1Institut für Geophysik und Meteorologie, Universität zu Köln — 2Johns Hopkins University, Baltimore, MD, USA — 3SouthWest Research Institute, San Antonio, TX, USA
We analyze a set of Hubble Space Telescope (HST) observations of the auroral UV emission from Jupiter's satellite Io and find a remarkably stable emission pattern over a period of 5 years.
Io is embedded in a dense plasma environment. Due to Jupiter's fast rotation the corotating plasma particles constantly flow past the moon. This flow of electrons and ions causes a complex plasma interaction and triggers auroral emission in the moon's atmosphere. The auroral emissions are often used as a tool to infer properties of both the satellite's plasma environment and its atmosphere. In our study we investigate 40 images of the spatially resolved OI1356 Å emission on Io's dayside atmosphere taken by the HST Space Telescope Imaging Spectrograph (STIS) between 1997 and 2001. We construct a phenomenological model for the three dimensional distribution of the local UV emission in Io's vicinity, which only depends on the properties of the ambient plasma. Model images, generated by integrating the local emission along the respective line-of-sight, show very good agreement with the 40 STIS observations for all major aurora features.