Jupiter’s mesmerizing auroral show (PJ13); HST ultraviolet observations near and far from Juno perijoves

After a 6-month period during which the separation angle between the Sun and Jupiter was too small to permit observations with Earth orbit telescopes, operation of the Hubble Space Telescope, supporting the Juno mission, was resumed (almost) in time for PJ11. We briefly review the main results of the previous part of this HST campaign, covering PJ03 to PJ07. We then present the newest results obtained during PJ11, PJ12 and PJ13. Most of the observing time allocated to this HST campaign was used during the first part of the campaign and allowed us to sample Jupiter’s aurora, not only near Juno’s perijoves, but also during the week before and the week after each perijove. During these times away from perijove, HST-STIS was the sole instrument able to provide high spatial and high temporal resolution dynamic images of Jupiter’s FUV aurora, which can be compared with measurements from Juno’s in situ instruments. Instead of presenting a statistical overview of the data, we have a more detailed look at some specific features revealed by the as yet unsurpassed STIS camera. In particular, we identify distinctive auroral phenomena, like explosive brightenings poleward of the main auroral emission. We present one such event, which we link to a strong perturbation of the magnetic field and of the energy distribution of the plasma particles concurrently observed with Juno. We suggest that the characteristics and the timing of this perturbation and of its associated auroral signature are consistent with a reconnection event.