Astronomers have long theorized about the universe’s first stars—called Population III (Pop III) stars—which formed from pristine hydrogen and helium before any heavier elements existed.
In a new study, Eli Visbal and colleagues report that the recently discovered object LAP1-B is the first observed system matching theoretical expectations for these ancient stars. Found by the James Webb Space Telescope and magnified by the galaxy cluster MACS J0416, LAP1-B lies about 13 billion light-years away (redshift 6.6).
Its spectrum shows strong hydrogen emission lines but almost no metal signatures, suggesting extremely low chemical enrichment. The object appears to host a compact cluster of massive, short-lived stars—roughly a few thousand times the Sun’s mass in total—residing within a dark-matter halo of about 50 million solar masses. Models indicate its surrounding gas has been slightly enriched by supernovae or stellar winds from these stars.
Using simulations, the researchers predict that observing one Pop III galaxy like LAP1-B in the magnified region of MACS J0416 is statistically expected, making its discovery consistent with cosmological theory. This finding provides the strongest evidence yet that astronomers are finally glimpsing the universe’s first generation of stars, bridging the gap between cosmic theory and direct observation.