Webb and Hubble find massive star clusters emerge faster

Astronomers using the NASA/ESA/CSA James Webb Space Telescope together with the NASA/ESA Hubble Space Telescope have looked deeply at thousands of young star clusters in four nearby galaxies, studying clusters at different ...

Astronomers have long known that understanding how star clusters come to be is key to unlocking other secrets of galactic evolution. Stars form in clusters, created when clouds of gas collapse under gravity. As more and more stars are born in a collapsing cloud, strong stellar winds, harsh ultraviolet radiation, and the supernova explosions of massive stars eventually disperse the cloud, ending star formation before all the gas is used up. Once the cloud of gas a star cluster was born in is gone, its light can bear down on other star-forming regions in the galaxy, too. This process is called stellar feedback , and it means that most of the gas in a galaxy never gets used for star formation. Researching how star clusters develop, then, can answer questions about star formation at a galactic scale.

Studies of the closest star-forming regions, in the Milky Way and the dwarf galaxies that orbit it, allow us to dissect star clusters in the smallest details, but our position in the disk of our galaxy means only a few such regions are visible to us. By observing nearby galaxies, astronomers can survey thousands of star-forming regions and characterize entire populations of star clusters at many stages of evolution—a feat made possible with the launch of space telescopes, most prominently the NASA/ESA Hubble Space Telescope. Both kinds of investigation are necessary to truly understand how star formation takes place in galaxies.

This image shows a section of one of the spiral arms of Messier 51 (M51), one of the four galaxies studied in this work, as seen by Webb’s Near-Infrared Camera (NIRCam). The thick clumps of star-forming gas are shown here in red and orange, representing infrared light emitted by ionised gas, dust grains, and complex molecules such as polycyclic aromatic hydrocarbons (PAHs). Within these gas complexes, each tens or hundreds of light years across, Webb reveals the dense, extremely bright clusters of massive stars that have just recently formed. The countless stars strewn across the arm of the galaxy, many of which would be invisible to our eyes behind layers of dust, are also laid bare in infrared light. Credit: ESA/Webb, NASA & CSA, A. Pedrini, A. Adamo (Stockholm University) and the FEAST JWST team Read more

This image shows the four galaxies studied in this research, each of which has previously been the subject of a Picture of the Month: Messier 51 (top left), Messier 83 (top right), NGC 4449 (bottom left), and NGC 628 (bottom right). Credit: ESA/Webb, NASA & CSA, A. Pedrini, A. Adamo (Stockholm University) and the FEAST JWST team Read more

This image locates a star-forming complex in one of the spiral arms of Messier 51 (M51), measuring almost 800 light-years across. M51 is located about 27 million light-years away from Earth. The thick cloud of star-forming gas, in which clumps collapsed to form each of the individual star clusters, is shown here in red and orange colours that represent infrared light emitted by ionised gas, dust grains, and complex molecules such as polycyclic aromatic hydrocarbons (PAHs). Many of the bright dots that can be seen within the clouds are star clusters. The massive young stars within cast powerful radiation on the gas clouds that surround them, creating the cyan illumination shown here. Eventually, the combination of radiation, stellar wind and the supernova explosions of the most massive of these stars will disperse the gas clouds, putting an end to the star formation in this part of M51. Credit: ESA/Webb, NASA & CSA, A. Pedrini, A. Adamo (Stockholm University) and the FEAST JWST team Read more