James Webb Telescope Observes an Exoplanet's Destruction in Real Time

The James Webb Space Telescope (JWST) has made a groundbreaking observation: the continuous and detailed atmospheric loss from an exoplanet. Essentially, the world's most powerful telescope has observed an exoplanet being destroyed in real time.

The exoplanet, named WASP-121b, is a gas giant that features two massive helium tails stretching across more than half its orbit around its star. This observation, made possible by the JWST in conjunction with the Canadian NIRISS instrument, provides an unparalleled, full-orbit view of how such planets shed their atmospheres.

The lead researcher, Romain Allart from the Trottier Institute for Research on Exoplanets (IREx), published these findings in the journal Nature Communications this month.

About WASP-121b

WASP-121b is classified as an ultra-hot Jupiter. It orbits incredibly close to its star, completing a full orbit in just 30 hours. This proximity exposes the planet's upper atmosphere to extreme radiation, heating it to thousands of degrees. Consequently, lighter elements like helium and hydrogen escape into space. This ongoing outflow gradually alters the planet's structure and composition.

Previously, scientists had only caught fleeting glimpses of this atmospheric escape as planets passed in front of their stars. Now, thanks to the JWST's sensitivity and the capabilities of NIRISS, Allart's team was able to continuously monitor WASP-121b for almost 37 hours. This covered more than one complete orbit, resulting in the most comprehensive record of an exoplanet to date.