Wolf-Rayet stars are in the process of casting off their outer layers, resulting in their characteristic halos of gas and dust. The new Webb images of a star called Wolf-Rayet 124 (WR 124) show this to great effect.
This image shows WR 124, a star located approximately 15,000 light-years away in the constellation of Sagitta. The star displays the characteristic diffraction spikes of Webb’s Near-infrared Camera (NIRCam), caused by the physical structure of the telescope itself. NIRCam effectively balances the brightness of the star with the fainter gas and dust surrounding it, while Webb’s Mid-Infrared Instrument (MIRI) reveals the nebula’s structure. Image credit: NASA / ESA / CSA / STScI / Webb ERO Production Team.
WR 124 is located approximately 15,000 light-years away in the constellation of Sagitta.
Also known as Merrill’s star, Hen 2-427, LBN 127, IRAS 19092+1646 and TIC 396769617, the star has a mass of 30 solar masses.
As the ejected gas moves away 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 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.
Despite the many essential roles that dust plays, there is still more dust in the Universe 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 wavelengths of light.
Webb’s Near-Infrared Camera (NIRCam) balances the brightness of WR 124’s stellar core and the knotty details in the fainter surrounding gas.
The telescope’s Mid-Infrared Instrument (MIRI) reveals the clumpy structure of the gas and dust nebula of the ejected material now surrounding the star.
Before Webb, dust-loving astronomers simply did not have enough detailed information to explore questions of dust production in environments like WR 124, and whether the dust grains were large and bountiful enough to survive the supernova and become a significant contribution to the overall dust budget. Now those questions can be investigated with real data.
Stars like WR 124 also serve as an analog to help astronomers understand a crucial period in the early history of the Universe.
Similar 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.
