Heat surge on a highly elliptical exoplanet
An international team of astronomers used the James Webb Space Telescope (JWST) to monitor the brightness and infrared spectrum of HD 80606 b, a gas giant roughly four times the mass of Jupiter that follows a highly elongated orbit around a Sun‑like star.
During the observation window covering the planet’s periapsis, JWST instruments recorded a swift rise in temperature. Measurements indicate that the planet’s atmospheric temperature jumped from about 500 K to over 1500 K within a few hours, reflecting intense stellar irradiation and rapid heating.
The findings are based on data from the Near‑Infrared Spectrograph (NIRSpec) and the Mid‑Infrared Instrument (MIRI). By combining both spectral ranges, researchers were able to map the thermal response of the planet to the brief but powerful stellar flash.
Presented at a scientific conference on Tuesday, the results provide new insight into the atmospheric dynamics of exoplanets experiencing extreme temperature variations. Scientists are particularly interested in how such rapid heating affects atmospheric circulation and chemistry.
JWST’s capability to capture these events opens the door to studying additional highly eccentric systems, expanding our understanding of planetary climate diversity. The team plans to observe future periapsis passages of HD 80606 b to track longer‑term atmospheric changes.