'Ribbon’ Wraps Up Mystery of Jupiter’s Magnetic Equator

New data from Jupiter observations is a gift to Leicester astronomers

Map of the infrared brightness of H3+ ions at the top of Jupiter’s atmosphere, The dark ribbon around the horizontal centre of the image reveals the location of Jupiter’s magnetic equator.

The discovery of a dark ribbon of weak hydrogen ion emissions that encircles Jupiter has overturned previous thinking about the giant planet’s magnetic equator.

This image is a map of the infrared brightness of H3+ ions at the top of Jupiter’s atmosphere reveals just how complex the ionosphere is. The two white regions at the top and bottom are the planet’s brilliant aurora. Glowing vastly brighter than the rest of the planet, they are here so saturated that no details can be see at all. Instead, the equatorial region can be seen. In the top left of the map, the previously observed darkening associated with the Great Cold Spot can be seen — the map now shows that this dark feature is only one of many within the ionosphere. The dark ribbon that undulates around the horizontal center of the image, wrapping around the planet from left to right, reveals the location of Jupiter’s magnetic equator. To the right of the image, above and below the dark ribbon, there are two very dark regions, a larger one in the north and a small circle in the south. We are not completely sure what these features are, but when the Juno spacecraft measured the magnetic fields in these regions, they were shown to be highly anomalous — perhaps these regions are similar to the Southern Atlantic magnetic anomaly on Earth.