Saturn's Northern Aurorae at Solstice From HST Observations Coordinated With Cassini's Grand Finale

Lamy, L. and Prangé, R. and Tao, C. and Kim, T. and Badman, S. V. and Zarka, P. and Cecconi, B. and Kurth, W. S. and Pryor, W. and Bunce, E. and Radioti, A. (2018) Saturn's Northern Aurorae at Solstice From HST Observations Coordinated With Cassini's Grand Finale. Geophysical Research Letters, 45 (18). pp. 9353-9362. ISSN 0094-8276

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Throughout 2017, the Hubble Space Telescope (HST) observed the northern far-ultraviolet aurorae of Saturn at northern solstice, during the Cassini Grand Finale. These conditions provided a complete viewing of the northern auroral region from Earth and a maximal solar illumination, expected to maximize the ionosphere-magnetosphere coupling. We analyze 24 HST images concurrently with Cassini measurements of Saturn's kilometric radiation and solar wind parameters predicted by two magnetohydrodynamic models. The aurorae reveal highly variable components, down to timescales of minutes, radiating 7 to 124 GW. They include a nightside-shifted main oval, unexpectedly frequent and bright cusp emissions, and a dayside low-latitude component. On average, these emissions display a strong local time dependence with two maxima at dawn and premidnight, the latter being newly observed and attributed to nightside injections possibly associated with solstice conditions. These results provide a reference frame to analyze Cassini in situ measurements, whether simultaneous or not.

Item Type:
Journal Article
Journal or Publication Title:
Geophysical Research Letters
Additional Information:
An edited version of this paper was published by AGU. Copyright 2018 American Geophysical Union. Lamy, L., Prangé, R., Tao, C., Kim, T., Badman, S. V., Zarka, P., et al. (2018). Saturn's northern aurorae at solstice from HST observations coordinated with Cassini's grand finale. Geophysical Research Letters, 45, 9353–9362. To view the published open abstract, go to and enter the DOI.
Uncontrolled Keywords:
?? auroramagnetosphereradio emissionssaturnsolar windgeophysicsearth and planetary sciences(all) ??
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26 Oct 2018 10:52
Last Modified:
01 Feb 2024 00:36