Free Astronomy Magazine May-June 2023

46 MAY-JUNE 2023 ASTRO PUBLISHING from the star and cools, cosmic dust forms and glows in the infrared light detectable by Webb. The origin of cosmic dust that can survive a supernova blast and con- tribute to the universe’s overall “dust budget” is of great interest to astronomers for multiple reasons. Dust is integral to the workings of the universe: It shelters forming stars, gathers together to help form planets, and serves as a platform for molecules to form and clump to- gether—including the building blocks of life on Earth. Despite the many essential roles that dust plays, there is still more dust in the uni- verse than astronomers’ current dust-formation theories can explain. The universe is operating with a dust budget surplus. Webb opens up new possibilities for studying details in cosmic dust, which is best observed in infrared The elusive prelude to a supernova by NASA/ESA/CSA Leah Ramsay Christine Pulliam T he rare sight of a Wolf-Rayet star – among the most lumi- nous, most massive, and most briefly-detectable stars known – was one of the first observations made by NASA’s James Webb Space Tele- scope in June 2022. Webb shows the star, WR 124, in unprecedented de- tail with its powerful infrared instru- ments. The star is 15,000 light-years away in the constellation Sagitta. Massive stars race through their life- cycles, and only some of them go through a brief Wolf-Rayet phase before going supernova, making Webb’s detailed observations of this rare phase valuable to astronomers. Wolf-Rayet stars are in the process of casting off their outer layers, re- sulting in their characteristic halos of gas and dust. The star WR 124 is 30 times the mass of the Sun and has shed 10 Suns’ worth of material—so far. As the ejected gas moves away