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| Titel |
HST/STIS observation of Ganymede's aurora: Investigating the variability of the auroral ovals |
| VerfasserIn |
Fabrizio Musacchio, Joachim Saur, Lorenz Roth, Stefan Duling, Paul D. Feldman, Darrell F. Strobel, Kurt D. Retherford, Melissa A. McGrath |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096129
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| Publikation (Nr.) |
 EGU/EGU2014-11616.pdf |
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| Zusammenfassung |
| We analyze the variability of Ganymede’s FUV auroral ovals using spectral images
acquired during two visits in 2010 and 2011 with Hubble’s Space Telescope Imaging
Spectrograph (HST/STIS) when Ganymede was at eastern elongation. The observed
electron-impact-excited auroral emissions from Ganymede’s O2 atmosphere are
thought to be driven by electron acceleration by strong field-aligned currents at the
separatrix, i.e., at the boundary area between open and closed magnetic field lines of
Ganymede’s mini-magnetosphere. The location of the auroral ovals correlates with the
intersection of this separatrix and the satellite’s surface and therefore strongly depends
on the interaction between Ganymede’s magnetic field and atmosphere with the
local time-variable plasma environment. In our study we particularly analyze the
latitudinal positions of the auroral ovals in order to better understand the correlation
with the plasma environment. The HST campaign was designed such that the full
range of Ganymede’s magnetic-latitudinal positions within Jupiter’s current sheet
is covered. We provide a mapping of auroral emission distribution and study the
auroral brightness as a function of Ganymede‘s position in Jupiter’s magnetosphere. |
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