Astronomers have confirmed the existence of auroras on Neptune for the first time, thanks to data obtained from NASA's James Webb Space Telescope (JWST) on March 26, 2024. While the Voyager 2 mission hinted at auroral activity in 1989, verification was previously impossible due to insufficient instrument sensitivity.
JWST's Near-Infrared Spectrograph (NIRSpec) enabled the detection of infrared auroras swirling in Neptune's atmosphere. The images also revealed that Neptune's ionosphere is cooling, showing a 10% temperature decrease compared to Voyager 2's observations 34 years ago.
Neptune's magnetic poles are significantly offset from its rotational poles, causing auroras to appear as irregular blobs near the equator. Further observations are planned for 2026 to investigate the cause of the ionospheric cooling.