Unprecedentedly Fast Winds Found on Exoplanet WASP-43b by James Webb Space Telescope

The discovery made by the James Webb Space Telescope (JWST) has revealed unprecedentedly fast winds on the exoplanet WASP-43b, located approximately 283 light-years away from Earth. This exoplanet is unique in that one side is constantly facing its sun, while the other remains in perpetual darkness. Comprised mainly of hydrogen and helium, WASP-43b is much hotter than any gas giant in our solar system due to its close proximity to its host star, completing an orbit every 19 Earth hours.

Scientists recently found that the temperature difference between the day and night sides of the planet drives powerful winds reaching speeds of up to 9,000 km/hour. Observations from the Hubble and Spitzer telescopes hinted at the presence of water vapor and clouds on the respective sides of WASP-43b, but it was the detailed measurements from Webb’s MIRI that provided a comprehensive understanding of the planet’s atmospheric dynamics. This groundbreaking study used Webb’s capabilities to monitor the temperature variations of different sides of the planet as they rotated into view over an entire orbit.

The dayside was found to have an average temperature of 1,250 degrees Celsius, while the cooler nightside registered 600 degrees Celsius. The data also identified the hottest spot on the planet, known as the “hotspot,” which is slightly offset to the east due to the influence of supersonic winds. Discovered in 2011, WASP-43b orbits a K-type star and was initially studied by the Hubble and Spitzer telescopes.

However, it was the JWST that provided new insights into the exoplanet’s atmosphere and weather patterns. This discovery sheds light on the complex interactions between temperature differentials and wind dynamics on distant exoplanets.