Astronomers reveal new insights into the factors influencing star formation efficiency in the densest regions of galaxies through Caffeine research.

In this groundbreaking study, astronomer Michael Mattern from the University of Paris-Saclay and his team meticulously mapped dense gas across 49 giant star-forming complexes located approximately 3,000 parsecs away within our galaxy’s disk.

“Creating stars is a challenging endeavor, and the process lacks efficiency,” the astronomers stated.

“Current understanding indicates that a certain minimum density of gas and dust is necessary for stars to form.”

“Only about 1 to 2 percent of the gas and dust in these regions is utilized in the ignition of a star.”

“Could denser regions exhibit higher efficiency in star formation?”

“We are examining GAL316, one of the remarkable stellar nurseries we observed, to explore this question,” they elaborated.

The ongoing CAFFEINE survey employs the ArTéMiS camera on the Atacama Pathfinder Experiment (APEX), a state-of-the-art radio telescope situated on the Chajnantor Plateau.

“APEX, managed by the Max Planck Institute for Radio Astronomy, has successfully captured the faint emissions of cold gas clouds, visible as blue glows in GAL316 images,” the researchers revealed.

“This glow overlays a starry backdrop, successfully recorded by ESO’s VISTA telescope.”

They discovered that as gas density increases past a specific threshold, the efficiency of star formation – the conversion rate of gas into stars – does not proportionately escalate.

This observation contradicts existing models that suggest a continual rise in star formation with density increases.

Conversely, the efficiency remains nearly constant in extremely dense gas, reinforcing the notion that stars primarily form within filamentous structures in clouds, a process dictated by the fragmentation of these filaments into protostar cores.

The findings suggest a potential gas density threshold for efficient star formation, bolstering the hypothesis that the physics of dense filaments governs star formation, rather than turbulence or feedback from nascent stars alone.

This research represents one of the most thorough efforts to date in connecting the physical structure of dense gas with star formation efficiency, paving the way for future observations and simulations that aim to elucidate the emergence of Sun-like stars from interstellar clouds.

“Our results indicate that the densest regions observed in this Caffeine study show similar efficiencies in star production compared to other stellar nurseries, provided they exceed the minimum density,” the scientists remarked.

Their findings are detailed in a published paper in the journal Astronomy and Astrophysics.

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M. Mattern et al. 2024. Investigating star formation efficiency in dense gas: Initial results from the CAFFEINE survey utilizing ArTéMiS. A&A 688, A163; doi: 10.1051/0004-6361/202449908