BepiColombo observations of cold oxygen and carbon ions in the flank of the induced magnetosphere of Venus
Résumé
On 10 August 2021, the Mercury-bound BepiColombo spacecraft performed its second y-by of Venus and provided a short-lived observation of its induced magnetosphere. Here we report results recorded by the Mass Spectrum Analyzer on board Mio, which reveal the presence of cold O+ and C+ with an average total ux of ~4 ± 1 × 104 cm−2 s−1 at a distance of about six planetary radii in a region that has never been explored before. The ratio of escaping C+ to O+ is at most 0.31 ± 0.2, implying that, in addition to atomic O+ ions, CO group ions or water group ions may be a source of the observed O+. Simultaneous magnetometer observations suggest that these planetary ions were in the magnetosheath ank in the vicinity of the magnetic
pileup boundary downstream. These results have important implications regarding the evolution of Venus’s atmosphere and, in particular, the evolution of water on the surface of the planet.
Domaines
Planète et Univers [physics]| Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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