James Web Space Telescope detailed observations of WR 124 Wolf Rayet star

In June 2022, NASA’s James Webb Space Telescope made one of its first observations, capturing the rare sight of a Wolf-Rayet star in unprecedented detail. The star, WR 124, is located in the constellation Sagittarius and is 15,000 light-years away.

Wolf-Rayet stars are among the most luminous, most massive, and seldom detected stars known. They are a rare prelude to the famous final act of massive stars: the supernova. Webb’s detailed observations of the Wolf-Rayet star, WR 124, displaying knotty structures and a history of episodic ejections, showcase a distinctive halo of gas and dust that frames the star and glows in the infrared light detected by Webb.

Despite being the scene of an impending stellar “death,” astronomers look to Wolf-Rayet stars for insight into new beginnings. Cosmic dust is forming in the turbulent nebulas surrounding these types of stars, which is composed of the heavy-element building blocks of the modern universe, including life on Earth.

Webb’s detailed observations of WR 124, which is 30 times the mass of the Sun and has shed 10 Suns’ worth of material so far, capture the star in the process of casting off its outer layers, resulting in its characteristic halos of gas and dust.

The origin of cosmic dust that can survive a supernova blast and contribute 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 together—including the building blocks of life on Earth. However, there is still more dust in the universe than astronomers’ current dust-formation theories can explain.

Webb’s powerful infrared instruments open up new possibilities for studying details in cosmic dust, which is best observed in infrared wavelengths of light. Webb’s Near-Infrared Camera balances the brightness of WR 124’s stellar core and the knotty details in the fainter surrounding gas. The telescope’s Mid-Infrared Instrument reveals the clumpy structure of the gas and dust nebula of the ejected material now surrounding the star.

Stars like WR 124 also serve as an analog to help astronomers understand a crucial period in the early history of the universe. Similar dying stars first seeded the young universe with heavy elements forged in their cores – elements that are now common in the current era, including on Earth.

Webb’s detailed image of WR 124 preserves forever a brief, turbulent time of transformation and promises future discoveries that will reveal the long-shrouded mysteries of cosmic dust.

The James Webb Space Telescope is the world’s premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency), and CSA (Canadian Space Agency).