Ancient star in Pictor II offers rare glimpse into early universe
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Astronomers have identified one of the oldest known stars, PicII-503, in the dwarf galaxy Pictor II, offering new insights into the early stages of the universe.
Located about 150,000 light-years from Earth, the star is considered a second-generation or Population II star, formed from material left behind by the first stars.
The findings, published in Nature Astronomy on March 16, 2026, highlight its extremely low metal content, with iron levels just 1/40,000th that of the Sun, making it one of the most metal-poor stars ever discovered beyond the Milky Way.
Scientists believe such stars formed after the earliest Population III stars ended their lives in supernova explosions, dispersing elements like carbon and iron into space. PicII-503’s chemical composition reflects this history, with a carbon-to-iron ratio more than 1,500 times higher than that of the Sun, consistent with some of the oldest stars found in the Milky Way’s outer halo.
The discovery was made by the MAGIC (Mapping the Ancient Galaxy in CaHK) project using the Dark Energy Camera on the Víctor M. Blanco Telescope. Follow-up observations from the Very Large Telescope and the Baade Magellan Telescope confirmed its unusually low levels of iron and calcium.
Lead researcher Anirudh Chiti of Stanford University said the star lies at the extreme edge of what scientists believed possible. Researchers say the finding helps trace the earliest chemical enrichment processes in faint dwarf galaxies, shedding light on how the first generations of stars shaped the cosmos.