Evidence for auroral influence on Jupiter’s nitrogen and oxygen chemistry revealed by ALMA
Résumé
The localized delivery of new long-lived species to Jupiter's stratosphere by comet Shoemaker-Levy 9 in 1994 opened a window to constrain Jovian chemistry and dynamics by monitoring the evolution of their vertical and horizontal distributions. However, the spatial distributions of CO and HCN, two of these long-lived species, had never been jointly observed at high latitudinal resolution. Atacama large millimeter/submillimeter array observations of HCN and CO in March 2017 show that CO was meridionally uniform and restricted to pressures lower than 3 ± 1 mbar. HCN shared a similar vertical distribution in the low-to mid-latitudes, but was depleted at pressures between 2 +2 −1 and 0.04 +0.07 −0.03 mbar in the aurora and surrounding regions, resulting in a drop by two orders of magnitude in column density. We propose that heterogeneous chemistry bonds HCN on large aurora-produced aerosols at these pressures in the Jovian auroral regions causing the observed depletion.
Domaines
Planète et Univers [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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