Overview

• The findings, led by Northumbria University’s Tom Stallard, were published in Geophysical Research Letters and presented at the EPSC-DPS 2025 meeting in Helsinki.
• A 10-hour JWST/NIRSpec session on November 29, 2024 captured near-infrared signals from H3+ in the ionosphere about 1,100 km up and methane in the stratosphere around 600 km.
• In the ionosphere, the data show dark bead-like features embedded within bright auroral halos that stayed coherent over hours and drifted slowly over longer timescales.
• Roughly 500 km below, a lopsided star-shaped structure with four visible arms extends from the north pole toward the equator, and mapping places both features over the same region with arms apparently above vertices of the cloud-level hexagon.
• The physical drivers are unknown, the signals are inaccessible to ground-based telescopes, and the researchers seek follow-up JWST observations to test magnetosphere–atmosphere coupling ideas during equinox conditions.