Heidelberg astronomers help uncover how dense stellar building blocks form in the Large Magellanic Cloud
Astronomers have obtained one of the sharpest views yet of the earliest stages of massive star formation in a galaxy beyond the Milky Way. Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international research team studied the star-forming region 30Dor-10 in the Large Magellanic Cloud and resolved compact dense structures of gas and dust at scales down to about 2,000 astronomical units. The study identifies 71 dense cores — the immediate precursors of stars — and provides the first observational constraints on the core mass function in an external galaxy.
The findings, published in Nature Communications, address a central question in astrophysics: whether the masses of stars are already determined at the stage when interstellar gas clouds fragment into dense cores, or whether stellar mass distributions are shaped later during the star-formation process. The team’s statistical analysis shows that the mass distribution of the dense cores in 30Dor-10 is consistent with a Salpeter-like slope, a classical benchmark in star-formation studies. This differs from the shallower, more top-heavy stellar mass distribution previously reported for stars in the wider 30 Doradus region, indicating that later evolutionary processes likely play a major role.
The observations focus on massive clumps in 30Dor-10, a prominent stellar nursery located in the broader 30 Doradus complex. ALMA’s high angular resolution allowed the researchers to show that structures previously seen as larger clumps break up into compact proto-clusters, each containing numerous dense cores. This provides a much more detailed view of how star formation proceeds in an environment shaped by intense radiation, low metallicity, and strong feedback from nearby massive stars.
“These observations allow us to study, how stellar nurseries are structured in a galaxy beyond our own. What we see is that the earliest dense building blocks of stars do not yet show the strongly top-heavy pattern inferred for the final stellar population. That tells us the environment continues to shape star formation after the initial fragmentation of the cloud.” said Prof. Dr. Ralf Klessen of the Institute for Theoretical Astrophysics (ITA) at the Centre for Astronomy of Heidelberg University and co-author of the science paper.
For Heidelberg researchers, the results are important because they are a fundamental test of understanding star-formation physics beyond the Milky Way. Until now, comparable measurements of the core mass function at this level of detail had only been possible in our own Galaxy. By showing that the earliest stages of fragmentation in 30Dor-10 remain consistent with a Salpeter-like distribution, the study strengthens the view that the final stellar mass distribution can evolve substantially over time through accretion, feedback, and dynamical interactions.
The paper, “The fragmentation properties of massive star-forming regions in 30Dor-10 at 2000 au resolution,” was published in Nature Communications on 22 April 2026.
ORIGINAL PUBLICATION
A. Traficante, M. J. Jiménez-Donaire, R. Indebetouw, T. Wong, A. Nucara, R. S. Klessen, P. Hennebelle, U. Lebreuilly, C. Mininni, S. Molinari, E. Sabbi, and J. D. Soler: The fragmentation properties of massive star-forming regions in 30Dor-10 at 2000 au resolution. Nature Communications 17, Article 3567 (2026).
ABOUT ZAH
The Centre for Astronomy of Heidelberg University (ZAH) brings together Heidelberg’s major university astronomy institutes and research groups across observational, theoretical, and computational astrophysics. Research at ZAH spans topics from exoplanets and nearby stars to the Milky Way, external galaxies, cosmology, instrumentation, and scientific computing. Prof. Dr. Ralf Klessen leads the Star Formation Group at the Institute for Theoretical Astrophysics (ITA), which is part of ZAH.
SCIENTIFIC CONTACT
Prof. Dr. Ralf Klessen
Centre for Astronomy of Heidelberg University (ZAH)
Institute for Theoretical Astrophysics (ITA)
Email: klessen@uni-heidelberg.de
CONTACT FOR MEDIA INQUIRIES
Dr. Guido Thimm
Centre for Astronomy of Heidelberg University (ZAH)
Email: thimm@uni-heidelberg.de
