Astronomers have published new results CAFFEINE studyshedding new light on a long-standing mystery: what controls the efficiency of star formation in the densest parts of galaxies?
This image shows the massive star-forming region GAL316. Image credit: ESO/M. Mattern/Andre et al./BBV.
In the study, University of Paris-Saclay astronomer Michael Mattern and his colleagues mapped dense gas in a sample of 49 nearby massive star-forming complexes at a distance of 3,000 parsecs in the galactic disk.
“Making a star is hard work and the process is not very efficient,” astronomers said in the statement.
“Current knowledge shows that for a star to form, the stellar cradle must have a minimum density of gas and dust.”
“Only 1-2% of all the gas and dust in these clouds is used to ignite the star.”
“But can even denser regions form stars more efficiently?”
“We are studying GAL316, one of many stellar nurseries we have observed, to answer this question,” they added.
The CAFFEINE study is conducted using the ArTéMiS camera at the Atacama Pathfinder Experiment (APEX), a radio telescope on the Chajnantor Plateau.
“Currently operated by the Max Planck Institute for Radio Astronomy, APEX detects the faint glow of cold gas clouds, which is visible as a blue glow in the GAL316 image,” the researchers said.
“This glow was superimposed on a background star captured by ESO's VISTA telescope.”
They found that the star formation efficiency (that is, the rate at which gas turns into stars) does not continue to increase as the gas becomes denser beyond a certain threshold.
This is contrary to models that predict a steady increase in star formation with increasing density.
Instead, the efficiency appears to remain nearly constant in very dense gas, supporting a picture in which stars form primarily in filamentary structures within clouds, a process determined by how these filaments fragment into protostellar cores.
The results also point to a possible gas density threshold at which star formation becomes efficient, lending weight to theories that star formation is governed by the physics of dense filaments rather than solely by turbulence or feedback from young stars.
The study represents one of the most comprehensive attempts to date to link the physical structure of dense gas to the efficiency of star formation, providing a clearer basis for future observations and modeling aimed at unraveling how stars like our Sun emerge from interstellar clouds.
“Our results indicate that the densest regions observed in this CAFFEINE study appear to be no more efficient at producing stars than any other stellar nurseries above a minimum density,” the scientists said.
Their paper was published in the magazine Astronomy and astrophysics.
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M. Mattern etc.. 2024. Understanding the efficiency of star formation in dense gas: first results from the CAFFEINE study with ArTéMiS. A&A 688, A163; two: 10.1051/0004-6361/202449908
