Astronomers have uncovered a new key to star formation: it’s not just how much gas a galaxy has, but where that gas is concentrated determines whether new stars are born.
Using CSIRO’s ASKAP radio telescope, researchers at the International Centre for Radio Astronomy Research (ICRAR) analyzed gas distribution across nearly 1,000 galaxies as part of the WALLABY survey. Their findings challenge long-standing assumptions about the relationship between gas content and star formation.
Lead author Seona Lee, a PhD student at the University of Western Australia node of ICRAR, highlighted the discovery’s significance. “It was very exciting to see a correlation between star formation and where the atomic hydrogen gas is located,” she said.
Traditionally, astronomers believed that galaxies with large amounts of gas were naturally more likely to produce stars. However, this new study reveals that sheer gas volume does not guarantee star formation. Instead, galaxies actively forming stars tend to have dense clusters of atomic hydrogen gas precisely where stars emerge.
Unusual signals emerging from the direction of the galactic center
This insight was made possible through the high-resolution capabilities of ASKAP, a powerful radio telescope operated by CSIRO, Australia’s national science agency. Earlier surveys could only map gas distribution in a few hundred galaxies, but WALLABY has dramatically expanded that scope.
Professor Barbara Catinella, Senior Principal Research Fellow at ICRAR and co-lead of the WALLABY survey, explained the concept using a simple analogy:
“Making stars is like baking a cake. Different cakes need different amounts of flour, but to bake a cake properly, you focus on the flour in the bowl—not the leftover flour still in the package. Similarly, studying star formation requires us to measure the atomic gas in the regions where stars form, rather than looking at total gas content across the galaxy.”
This breakthrough provides deeper insights into how galaxies evolve. The ability to track gas distribution with greater accuracy will help scientists refine models of galaxy growth and better understand the mechanisms behind star birth.
Starry tail describes the evolution of a dwarf galaxy
Lee emphasized the importance of continued research: “To understand how stars are formed truly, we must examine the atomic hydrogen gas exactly where stars are actively coming to life. This is essential to determining how much gas directly fuels star creation.”
With tools like ASKAP enabling broader observations, researchers are poised to uncover even more about the dynamic processes shaping the universe.
Journal Reference:
- Lee S, Catinella B, Westmeier T, et al. WALLABY pilot survey: Spatially resolved gas scaling relations within the stellar discs of nearby galaxies. Publications of the Astronomical Society of Australia. 2025;42:e046. DOI: 10.1017/pasa.2025.30
