JunoCam at PJ41 / 2022/23 report no.1

–John Rogers (2022 April 29)

Juno’s perijove-41 occurred on 2022 April 9.  This was just as the planet was beginning to appear in the dawn sky for ground-based observers, so Juno’s coverage was very important for assessing what had happened during solar conjunction.  Some good amateur images were obtained in the week following.  In this report we summarise the state of Jupiter’s features as revealed by JunoCam and by amateur observers.

We particularly wanted to know how the NEB had developed, and the results are very informative. Amateur images showed that the dark brown ‘barges’ are still present but fading, and there is a single active sector in the NEB(S); analysis by Shinji Mizumoto shows that this is the same active sector of  NEB(S) as in late 2021.  JunoCam images showed strips of the NEB not only at perijove, but also on the opposite side while inbound.  Altogether they showed 3 AWOs, 2 fading barges, the active outbreak region on the NEB(S), and a general tendency of the brown NEB(S) to expand northwards.  In summary, the mid-NEB has somewhat darkened and the NEBs carries small features at all longitudes, but it is not yet clear whether this is the full NEB Revival.  Possibly the stormy sector in the NEB(S) is only driving rather superficial changes further north, not the kind of vigorous spreading convection that we expected, in which case it could all settle down again.  On the other hand, it could all continue to develop this year – ongoing observations will be vital.

Here is the report, with miniature figures (PDF):   Report-on-PJ41&Minifigs

Here are the full-size figures (ZIP file, 7.2 MB):  PJ41-report_Figures

Here are parts of the global map, showing the NEB and the STB regions: