The papers in brief * NASA'sJames Webb Space Telescope (JWST) was launched in December 2021 and now orbits the Sun, some 1.5 million kilometres from Earth. * Early data released last year confirm that this is an ideal vantage point for investigating exoplanets - the distant worlds that orbit stars other than the Sun. * Five papers in Nature report analyses profiling the atmospheric chemistry ofWASP-39b, a hot exoplanet with a Saturn-like mass. * The studies settle questions about this exoplanet's atmosphere, and showcase the power and versatility ofJWST. In all five investigations, the teams found that elements heavier than hydrogen and helium are more abundant in the atmosphere of WASP-39b than they are in the Sun, whereas the ratio of carbon to oxygen is lower than that of the Sun and commensurate with that of Saturn. The ratio measured for WASP-39b indicates that the planet might have formed at a location beyond the system's water-ice line - the distance from the host star at which it is cold enough for compounds such as water and carbon dioxide to condense into solid ice.