NASA's James Webb Telescope Maps Alien Planet's Atmosphere

NASA's James Webb Space Telescope has successfully created the first three-dimensional map of an alien planet's atmosphere. This groundbreaking achievement focuses on the gas giant WASP-18b, located approximately four hundred light-years from Earth.

Using a technique called eclipse mapping, researchers identified various temperature zones within the planet's atmosphere. The technique allows scientists to analyze exoplanets that cannot be observed directly due to the brightness of their host stars.

As WASP-18b passes behind its star, the star blocks increasing amounts of light reflected from the planet, which enables scientists to measure how this light changes. According to Ryan Challener, a co-author of the study and researcher at Cornell University, this method provides insights into exoplanets similar to those in our solar system.

WASP-18b is a massive planet, roughly ten times the mass of Jupiter, and it orbits its star in just twenty-three hours. Importantly, the planet is tidally locked, meaning one hemisphere constantly faces its star while the other remains in darkness.

The new three-dimensional map builds on earlier two-dimensional temperature data of WASP-18b, using different wavelengths of light to reveal temperature variations at various altitudes within the atmosphere.

Notably, water absorption data was utilized to map the exoplanet's wet upper atmosphere, while wavelengths not absorbed by water allowed for observations at lower altitudes. The researchers discovered two distinct temperature regions on the planet's day side, including a circular hotspot directly facing the star and a colder ring extending to the planet's edge.

This suggests that atmospheric winds are insufficient to redistribute heat from the star evenly across the planet. Interestingly, the study found that the hotspot exhibited less water content than the planet's average atmosphere, leading researchers to propose that the extreme temperatures in this area might be breaking down water molecules.

Challener noted that this observation aligns with theoretical predictions, marking an exciting advancement in our understanding of WASP-18b's atmospheric conditions. Further observations with the James Webb Space Telescope could enhance the resolution of the atmospheric map and enable scientists to explore the atmospheres of similar gas giants in greater detail.

This study was published on October 28 in the journal Nature Astronomy, representing a significant leap forward in exoplanet research.