Researchers from the University of Chicago, renowned for deep-space studies, have identified one of the oldest stars in the Universe. This second-generation star sits in the Large Magellanic Cloud, a small companion galaxy to the Milky Way. The findings appear in the journal Nature Astronomy (NatAstro).
Second-generation stars arise from materials produced by the explosive deaths of earlier stars. Their birth marks a new chapter in galactic chemistry, as elements forged in stellar furnaces are dispersed and later incorporated into newer stars.
To hunt for these ancient objects, scientists surveyed the Large Magellanic Cloud, first using the European Space Agency’s Gaia satellite to flag promising candidates and then employing the Magellan Telescope in Chile for detailed follow-up observations. This two-step approach helped assemble a catalog of ten such stars, each offering clues about the early universe.
Among the survey cohort, one star stood out because it contained far fewer heavy elements than any other star observed in the Large Magellanic Cloud. This scarcity of heavy elements suggests a formation at a very early epoch, before repeated cycles of stellar birth and death enriched the surrounding gas. In other words, it likely formed after the very first generation of stars but before the interstellar material had been heavily enriched by successive supernovae and stellar winds.
Astroarchaeologist Anirudh. Chiti described the star as a rare and valuable window into the process that seeds galaxies beyond the Milky Way with the first heavy elements. While the Milky Way has its own established patterns of chemical enrichment, it remains an open question whether those signatures are universal or specific to our galaxy. The star’s composition provides a tangible data point to test that idea and to refine models of early element formation across galaxies (NatAstro; attribution: Nature Astronomy, 2024).
The rarity of second-generation stars is striking. Estimates indicate fewer than one object of this class per 100,000 stars in the Milky Way. The oldest second-generation stars are thought to be about 13.5 billion years old, placing them just a few hundred million years younger than the universe itself. These ancient objects act like cosmic fossils, preserving the chemical fingerprints of the earliest epochs and offering a tangible record of how galaxies build up their elemental inventories over cosmic time (NatAstro; attribution: Nature Astronomy, 2024).
In the broader context of cosmic history, researchers continue to refine chronology and formation pathways for the earliest stellar generations. Each newly identified relic helps scientists test theories of gas cooling, element synthesis, and the role of supernovae in seeding galaxies with the elements essential for planet formation and, ultimately, life. The ongoing effort to map second-generation stars in nearby galaxies not only broadens the scope of stellar archaeology but also strengthens the connection between local observations and the distant, formative epochs of the universe (NatAstro; attribution: Nature Astronomy, 2024).
As observational capabilities advance, more stars like this rare second-generation object may be found in nearby dwarf galaxies. Such discoveries will sharpen our understanding of how the first heavy elements emerged, how quickly they spread, and how early stellar populations influenced the chemical landscapes of larger galaxies that followed. The pursuit remains a dynamic frontier in astronomy, with every ancient star acting as a guide to the cosmos’s earliest chapters (NatAstro; attribution: Nature Astronomy, 2024).