One of the first observations made by NASA’s James Webb Space Telescope in June 2022 was the rare sighting of the Wolf-Rayet star, one of the brightest, most massive and short-lived stars. Webb shows the WR 124th star in unprecedented detail thanks to powerful infrared instruments. The star is located 15,000 light-years away in the constellation Sagittarius.

Massive stars go through their life cycles, and only a few go through a brief Wolf-Rayet stage before turning supernova, making Webb’s detailed observations of this rare stage valuable to astronomers. Wolf-Rayet stars are in the process of shedding their outer layers resulting in characteristic halos of gas and dust. The star WR 124 has 30 times the mass of the Sun and has ejected 10 Suns worth of material so far. As the ejected gas moves away from the star and cools, cosmic dust forms and glows in the infrared light detected by Webb.

The origin of cosmic dust, which can survive a supernova explosion and contribute to the overall “dust budget” of the universe, is of great interest to astronomers for several reasons. Dust is an integral part of how the universe works (see infographic above): it protects stars in formation, clumps together to help form planets, and serves as a platform for molecules, including the building blocks of life, to form and stick together. Soil. Despite the many important roles dust plays, there is more dust in the universe than astronomers’ current theories of dust formation can explain. The universe is working on a budget surplus.

Webb opens up new possibilities for studying the details of cosmic dust best observed in the infrared wavelength range. The Webb Near Infrared Camera (NIRCam) stabilizes the brightness of WR 124’s stellar core and knotty details in the fainter surrounding gas. The telescope’s Mid-Infrared Instrument (MIRI) shows the complex structure of the gas-dust nebula, which is made up of ejected material currently surrounding the star. Before Webb, dust-loving astronomers didn’t have enough detailed information to investigate dust formation in environments like WR 124 and whether dust grains were large and abundant enough to survive a supernova and contribute significantly to the overall dust budget. . Now these questions can be explored with real data.

Stars like WR 124 also serve as analogues to help astronomers understand a pivotal period in the early history of the universe. Such dying stars first seeded the young universe with heavy elements processed in their cores – elements common today, including on Earth today.