Europa and Ganymede's Water-Product Exospheres
Résumé
Europa and Ganymede are thought to possess globally similar exospheres, in spite of the possibility that Europa is currently cryovolcanically active, and Ganymede's intrinsic magnetic field. Ions in Jupiter's magnetosphere bombard the icy surfaces, and produce predominantly O2, with slightly less H2O and H2 due to freezing and escape respectively. We investigate and compare the water-product exospheres of the two satellites under rotation, using our 3-D Exosphere Global Model (EGM). In previous works ([1], [2]), we focused on the near-surface z < 1.25rs , oxidized component of the exosphere, dominated by thermal-ized O2 , which undergoes a dusk-over-dawn asymmetry due to diurnal solar insolation of the surface over the satellite's orbit. This was observed by asymmetries in oxygen aurorae. Here, we focus on characterizing the hydrogen-species: H, H2 , and H2O which have been far more elusive as lyman-α auroral emission has multiple production pathways, even in the absence of endogenic sources.
Domaines
Planète et Univers [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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