Carbon dioxide in an exoplanet atmosphere

The James-Webb-Telescope provides insights into the composition and formation of planets outside our solar system. Using the James Webb Space Telescope, an international collaboration of astronomers with Laura Kreidberg of the Max Planck Institute for Astronomy has captured infrared light filtered through the atmosphere of a hot gas giant 700 light-years away. The transmission spectrum of exoplanet WASP-39 b represents a hat trick of firsts: Webb's first official scientific observation of an exoplanet; the first detailed exoplanet spectrum covering this range of near-infrared colours; and the first indisputable evidence for carbon dioxide in the atmosphere of a planet orbiting a distant star. The results indicate Webb's ability to spot key molecules like carbon dioxide in a wide variety of exoplanets - including smaller, cooler, rocky planets - providing insights into the composition, formation, and evolution of planets across the galaxy. Illustration showing what exoplanet WASP-39 b could look like, based on current understanding of the planet. WASP-39 b is a hot, puffy gas-giant planet with a mass 0.28 times Jupiter (0.94 times Saturn) and a diameter 1.3 times greater than Jupiter, orbiting just 0.0486 astronomical units (7,270,000 km) from its star. The star, WASP-39, is fractionally smaller and less massive than the Sun.