“Three years into its mission, Webb continues to deliver on its design – revealing previously hidden aspects of the universe, from the star formation process to some of the earliest galaxies,” said Shawn Domagal-Goldman, acting director of NASA’s Astrophysics Division. That promise was fulfilled again this July, when the James Webb Space Telescope (JWST) celebrated its third birthday by gazing deep into the Cat’s Paw Nebula revealing a collection of young stars congregated within the nebula’s so-called “toe beans.”
The Cat’s Paw Nebula, NGC 6334, is in no way an ordinary star-forming region. About 4,000 light-years away, in the Scorpius constellation, it’s a world of extremes where 200,000 suns’ worth of material forms new stars at a very high frequency some becoming 30 to 40 times more massive than our Sun (NGC 6334 producing stars at a higher rate than Orion). The nebula is going through what astronomers refer to as a “mini-starburst,” with tens of thousands of recently born stars, more than 2,000 of which remain wrapped in dense veils of dust.
Webb’s Near-Infrared Camera (NIRCam) made this discovery. Its sensitivity to light in the 0.6 to 5 micron range enables it to cut through the deep dust veils that long have hid the nebula’s youngest stars from optical telescopes. Giant young stars are shredding their way through surroundings in the new images, carving out cavities in the gas and dust using their powerful radiation and lighting up a blue-hued nebular glow. The orange-brown stratifications in the photograph determine stardust, where red-colored clumps indicate the regions of current massive star formation (glowing red dots indicate where massive star formation is occurring).
The technical feat extends beyond skin deep. Webb’s NIRCam offers unprecedented infrared spatial resolution, even exceeding the Hubble and Spitzer telescopes. This has made it possible for astronomers to spot individual protostars and dust filaments, some of which are so dense they appear as “empty” blocks and contain the seeds of future stars. In one theatrical sense, the reddish-orange oval near the top center of the image probably indicates a region of high density starting the process of star formation, by the fact that no background stars are visible shining through.
The Cat’s Paw Nebula provides a natural laboratory to observe the chaotic evolution from cloud to star. Star formation in these kinds of regions is controlled by a multifaceted interplay of gravity, turbulence, and stellar feedback from newly created, young, and massive stars. Turbulent motions within molecular clouds, both compressive and solenoidal, have been observed by recent work to affect directly the efficiency of star formation (turbulence and star formation efficiency in molecular clouds). In NGC 6334, the supersonic turbulence is supposed to slow down and speed up star formation: collapse is avoided in one region, whereas compressive flows in another initiate the formation of massive stars. Measurements in other similar clouds have indicated that what is now referred to as high-velocity turbulence is in fact the entanglement of several substructures, and that pressures in the external environment (not simply internal motion within the gas) are important factors in the development of dense protostellar cores.
Webb’s technological capabilities are more than just the Cat’s Paw. In just the last year alone, it has broken its own record by mapping almost 800,000 galaxies in cosmic history and directly imaging exoplanets using its coronagraph (largest universe map ever produced). Its infrared sensitivity made out galaxies as they existed shortly after the Big Bang, a mere few hundred million years ago, and delivered critical data for insight into how matter initially came together to form stars and galaxies.
But as Domagal-Goldman described, “the questions Webb has raised are just as exciting as the answers it’s giving us.” The Cat’s Paw Nebula, with its explosion of star birth and gentle dance of turbulence and gravity, offers us a glimpse into the processes that have sculpted the Milky Way and others throughout the universe since the beginning of time.
