Ancient Oxygen in a 300‑Million‑Year‑Old Galaxy Reveals Early Stellar Enrichment

ALMA detected the ionised oxygen [O III] 88 μm line in JADES-GS-z14-0, a galaxy seen when the universe was under 300 million years old (z ≈ 14.18), confirming rapid heavy‑element production by early generations of massive stars. The inferred abundances are about 5–20% of solar (around 17% in some models), indicating fast chemical enrichment, while not pinning down specific stellar histories or supernovae.