Free Astronomy Magazine January-February 2024

JANUARY-FEBRUARY 2024 stars in the image is a cluster of pro- tostars – stars that are still forming and gaining mass – producing out- flows that glow like a bonfire in the midst of an infrared-dark cloud. At the heart of this young cluster is a previously known, massive protostar over 30 times the mass of our Sun. The cloud the protostars are emerg- ing from is so dense that the light from stars behind it cannot reach Webb, making it appear less crowded when in fact it is one of the most densely packed areas of the image. Smaller infrared-dark clouds dot the image, looking like holes in the starfield. That’s where future stars are forming. Webb’s NIRCam (Near-Infrared Cam- era) instrument also captured large- scale emission from ionized hydro- gen surrounding the lower side of the dark cloud, shown cyan-colored in the image. Typically, Crowe says, this is the result of energetic pho- tons being emitted by young mas- sive stars, but the vast extent of the region shown by Webb is something of a surprise that bears further in- vestigation. Another feature of the region that Crowe plans to examine further is the needle-like structures in the ion- ized hydrogen, which appear ori- ented chaotically in many directions. “The galactic center is a crowded, tumultuous place. There are turbu- lent, magnetized gas clouds that are forming stars, which then impact the surrounding gas with their out- flowing winds, jets, and radiation,” said Rubén Fedriani, a co-investiga- tor of the project at the Instituto de Astrofísica de Andalucía in Spain. “Webb has provided us with a ton of data on this extreme environ- ment, and we are just starting to dig into it.” Around 25,000 light-years from Earth, the galactic center is close enough to study individual stars with the Webb telescope, al- lowing astronomers to gather un- precedented information on how stars form, and how this process may depend on the cosmic environ- ment, especially compared to other regions of the galaxy. For example, are more massive stars formed in the center of the Milky Way, as op- posed to the edges of its spiral arms? “The image from Webb is stunning, and the science we will get from it is even better,” Crowe said. “Mas- sive stars are factories that produce heavy elements in their nuclear cores, so understanding them better is like learning the origin story of much of the universe.” ! [NASA, ESA, CSA, STScI, Samuel Crowe (UVA)]