Jupiter's North Pole Remains a Mystery in PJ05 Approach Footprint

2017-04-10 11:48 UT
Credit : NASA / JPL / SwRI / MSSS / Gerald Eichstädt
Submitted By : Maquet-80
Mission Phase : PERIJOVE 5

During Perijove-05 approach, JunoCam took one RGB image each half an hour. Since Jupiter rotates once each about 10 hours, a sequence of 20 JunoCam approach images covers one Jupiter rotation. Currently, there is winter on Jupiter's northern hemisphere. This leaves the north pole in the dark. The merged deLambertianed polar projections of such a 20 images sequence therefore leave a dark spot around the north pole. DeLambertianing is a crude method to adjust for brightness variations induced by the solar incidence angle varying over the illuminated surface of Jupiter. Jupiter's twilight zone is brighter than this simple model predicts. This results in an overenhancement of the twilight zone. The merged polar map covers 20 such overenhanced twilight zones, summing up to a nice spiral pattern, as Juno's perspective grows more and more north polar during approach.