Journal article
Alternating North-South Brightness Ratio of Ganymede's Auroral Ovals: Hubble Space Telescope Observations Around the Juno PJ34 Flyby
Geophysical research letters, Vol.49(23), e2022GL098600
12/16/2022
DOI: 10.1029/2022GL098600
Abstract
We report results of Hubble Space Telescope observations from Ganymede's orbitally trailing side which were taken around the flyby of the Juno spacecraft on 7 June 2021. We find that Ganymede's northern and southern auroral ovals alternate in brightness such that the oval facing Jupiter's magnetospheric plasma sheet is brighter than the other one. This suggests that the generator that powers Ganymede's aurora is the momentum of the Jovian plasma sheet north and south of Ganymede's magnetosphere. Magnetic coupling of Ganymede to the plasma sheet above and below the moon causes asymmetric magnetic stresses and electromagnetic energy fluxes ultimately powering the auroral acceleration process. No clear statistically significant timevariability of the auroral emission on short time scales of 100s could be resolved. We show that electron energy fluxes of several tens of mW m(-2) are required for its OI 1,356 angstrom emission making Ganymede a very poor auroral emitter.
Details
- Title: Subtitle
- Alternating North-South Brightness Ratio of Ganymede's Auroral Ovals: Hubble Space Telescope Observations Around the Juno PJ34 Flyby
- Creators
- Joachim Saur - University of CologneStefan Duling - University of CologneAlexandre Wennmacher - University of CologneClarissa Willmes - University of CologneLorenz Roth - KTH Royal Institute of TechnologyDarrell F. Strobel - Johns Hopkins UniversityFrederic Allegrini - Southwest Research InstituteFran Bagenal - University of Colorado BoulderScott J. Bolton - Southwest Research InstituteBertrand Bonfond - University of LiègeGeorge Clark - Johns Hopkins University Applied Physics LaboratoryRandy Gladstone - Southwest Research InstituteThomas K. Greathouse - Southwest Research InstituteDenis C. Grodent - University of LiègeCandice J. Hansen - Planetary Science InstituteWilliam S. Kurth - University of IowaGlenn S. Orton - California Institute of TechnologyKurt D. Retherford - Southwest Research InstituteAbigail M. Rymer - Johns Hopkins University Applied Physics LaboratoryAli H. Sulaiman - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.49(23), e2022GL098600
- Publisher
- Amer Geophysical Union
- DOI
- 10.1029/2022GL098600
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Number of pages
- 8
- Grant note
- 80NM0018D0004 / NASA; National Aeronautics & Space Administration (NASA) 884711 / European Research Council (ERC) under the European Union; European Research Council (ERC) HST-GO-16499.006-A; NAS5-26555 / STScI under NASA
- Language
- English
- Date published
- 12/16/2022
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455543102771
Metrics
1 Record Views