The James Webb Space Telescope (JWST) has provided stunning views using its sophisticated suite of infrared instruments and spectrometers. The latest images reveal numerous impressive features in the Sagittarius B2 molecular cloud, the most massive and active star-forming region in the Milky Way. By combining data from its Mid-Infrared Instrument (MIRI) and Near-Infrared Camera (NIRCam), Webb captured Sgr B2 in multiple wavelengths, providing a contrasting view that showcases its massive stars and glowing cosmic dust in unprecedented detail.
While the interstellar gas and dust appear bright and vivid in mid-infrared light, the brightest stars are not visible. Meanwhile, the shorter wavelength captured by the NIRCam features several large and colorful stars while the gas and dust glows less intensely. These observations will help astronomers better understand the history and process of stellar formation in the Milky Way’s dense, active central region. As Adam Ginsburg, an astronomer at the University of Florida and the principal investigator of the program, explained:
Webb’s powerful infrared instruments provide detail we’ve never been able to see before, which will help us to understand some of the still-elusive mysteries of massive star formation and why Sagittarius B2 is so much more active than the rest of the galactic center.
Webb’s MIRI instrument shows the Sagittarius B2 region in mid-infrared light. Credit: NASA/ESA/CSA/STScI
Sgr B2 is located only a few hundred light-years from Sagittarius A*, the supermassive black hole at the center of our galaxy, which significantly influences the evolution of stars in the galactic core. The region is also densely packed with stars, star-forming clouds, and complex magnetic fields, making it difficult to visualize with conventional instruments. Webb’s instruments allow it to detect infrared light that passes through some of the region’s thicker clouds, revealing young stars and the clouds of gas and dust surrounding them.
However, some spots in the cloud are not visible to Webb’s instruments because they are so dense in gas and dust. These clouds are essentially reservoirs of material that feed star formation in Sgr B2 and resemble empty space. Only the brightest stars are able to shine through the veil of gas and dust and appear in both images as bright blue dots.
Despite being so densely packed, star formation is disproportionately low in this region of the galaxy compared to the galactic disk. This is not the case for Sgr B2, which produces fifty percent of the region’s stars despite having only ten percent of the galactic center’s material. Astronomers hope that Webb’s observations will shed light on this mystery and improve our understanding of the life cycle of stars and how galaxies evolve with time. Said Nazar Budaiev, a graduate student at the University of Florida and the co-principal investigator of the study:
Humans have been studying the stars for thousands of years, and there is still a lot to understand. For everything new Webb is showing us, there are also new mysteries to explore, and it’s exciting to be a part of that ongoing discovery.
Further Reading: NASA