Recent observations from NASA’s Webb Space Telescope have revealed that star formation in nearby galaxies is not only occurring within the spiral arms but also in galactic spurs, which are tendrils connecting the spiral arms through extensions of gas, dust, and molecular clouds. These observations, part of the PHANGS project, have been described as revolutionary in deepening our understanding of the first phases of star formation and the interstellar medium.
Lead author Thomas Williams of the University of Oxford explains that most stars form in the disk of a galaxy, but the surprising revelation from these observations is that star formation is happening outside the traditional spiral structure of these galaxies as well. These findings have shown that galactic spurs are a common feature in various galaxies, and they seem to be associated with ongoing star formation.
Despite the discovery of these galactic spurs, their structure and stability in a rotating galaxy remain a mystery. Williams suggests that these spurs are likely transient structures that move along with the galaxy itself. This insight into the messier aspects of star formation and galaxy structure challenges previous assumptions about the nature of galaxy evolution. While our Milky Way has not yet shown evidence of galactic spurs, other galaxies like the Triangulum Galaxy demonstrate similar features.
Williams explains that star formation in galaxies begins with the creation of dust from exploding massive stars. This dust serves as a site for chemical reactions that eventually lead to the formation of giant molecular clouds, where new stars are born. The Webb telescope’s capabilities have allowed researchers to pinpoint the locations of very young stars, some less than a million years old, within these galaxies.
The PHANGS project aims to study a total of 90 nearby galaxies to better understand the early stages of star formation and how it varies across different galaxies. By cataloging the spurs between the spirals and analyzing a wealth of new data, researchers hope to gain insight into the complex processes that shape galaxy evolution and ongoing star formation. Williams emphasizes the importance of comparing these observations with existing simulations to refine our understanding of how galaxies work.
While these recent observations have provided valuable insights into star formation in nearby galaxies, there is still much to learn about the intricate processes that drive galaxy evolution. Continued research and analysis of data from the Webb telescope and other instruments will contribute to a more comprehensive understanding of the universe’s vast and complex structures.
