One of the biggest advantages of NASA's James Webb Space Telescope is its ability to provide astronomers with detailed views of the regions where new stars are born. The latest example shown in new images from the Webb Mid-Infrared Instrument (MIRI) is NGC 346, the brightest and largest star-forming region in the Small Magellanic Cloud.
New infrared images of NGC 346 from NASA's James Webb Space Telescope's Mid-Infrared Instrument (MIRI) track emissions from cold gas and dust. In this image, blue represents silicates and soot chemical molecules called polycyclic aromatic hydrocarbons (PAHs). The red radiation from warm dust heated by the brightest and most massive stars in the center of the region is more diffuse. Bright patches and filaments mark regions that harbor large numbers of protostars. Source: NASA, ESA, CSA, STScI, Nolan Habel (NASA-JPL), Patrick Kavanagh (Maynooth University)
Because cosmic dust is formed from heavy elements such as silicon and oxygen, scientists don't expect the SMC to contain large amounts of dust. However, new MIRI images, as well as images of NGC 346 from the Webb Near-Infrared Camera released in January, show large amounts of dust in the area.
In this representative color image, blue tendrils trace emissions of substances containing dusty silicates and soot chemical molecules called polycyclic aromatic hydrocarbons, or PAHs. Warm dust heated by the brightest, most massive stars at the center of the region emits a more diffuse red emission. The arc to the left of center may be a reflection of light from a star near the center of the arc. (Similar, fainter arcs appear in the lower left and upper right corners, associated with stars.) Finally, bright patches and filaments mark regions with large numbers of protostars. The team searched for the reddest stars and found 1,001 pinpoint sources, most of which were young stars still embedded in dusty cocoons.
By combining Webb data in the near- and mid-infrared, astronomers are able to conduct a more comprehensive census of stars and protostars in this dynamic region. The results have important implications for our understanding of galaxies that existed billions of years ago, during a time known as "cosmic noon," when star formation was at its peak and heavy element concentrations were low.