A mysterious radio signal from a distant exoplanet has stunned scientists - Futura, le média qui explore le monde

Webb observations reveal a hotter, more extended evening edge in the atmosphere of the giant exoplanet WASP-17b. A method called transmission strings maps atmospheric differences around the planet’s apparent outline during transit. The inferred temperature contrast is about 650 kelvin, while water and carbon dioxide abundances remain broadly consistent around the limb. One edge of WASP-17b stretches farther into space than the other. Around this swollen gas giant, intense heating and atmospheric circulation produce differences that disappear when astronomers treat the entire atmosphere as one uniform ring. A new analysis has recovered some of that missing structure from starlight filtered through the planet’s atmosphere. The findings, published in Nature Astronomy, concern a hot Jupiter roughly 1,300 light-years from Earth. A team co-led by Cornell University and the University of Bristol applied a method called transmission strings to James Webb Space Telescope observations. The approach traces atmospheric properties at different positions around the planet’s apparent edge.