The Large Magellanic Cloud (LMC) is the Milky Way’s most massive satellite galaxy, which only recently (~2 billion years ago) fell into our Galaxy. As stellar atmospheres preserve the composition of their natal cloud, the LMC’s recent infall makes its most ancient, metal-deficient (‘low-metallicity’) stars unique windows into early star formation and nucleosynthesis in a formerly distant region of the high-redshift universe. Here we present the elemental abundances of ten stars in the LMC with iron-to-hydrogen ratios ranging from ~1/300th to ~1/12,000th that of the Sun. Our most metal-deficient star is markedly more metal-deficient than any in the LMC with available detailed chemical abundance patterns and was probably enriched by a single extragalactic ‘first-star’ supernova. This star lacks appreciable carbon enhancement, as does our overall sample, unlike the lowest-metallicity stars in the Milky Way. This and other abundance differences affirm that the extragalactic early LMC experienced diverging enrichment processes compared to the early Milky Way. Early element production, driven by the earliest stars, thus, appears to proceed in an environment-dependent manner.

大麦哲伦星云 (LMC) 是银河系最大的卫星星系，最近（约 20 亿年前）才落入我们的银河系。由于恒星大气保留了其诞生云的成分，大麦哲伦最近的陨落使其最古老的、缺乏金属（“低金属丰度”）的恒星成为了解高红移宇宙的一个遥远区域的早期恒星形成和核合成的独特窗口。在这里，我们展示了大麦哲伦星云中十颗恒星的元素丰度，其铁氢比范围为太阳的约 1/300 至约 1/12,000。我们最缺乏金属的恒星明显比 LMC 中任何具有可用详细化学丰度模式的恒星都更缺乏金属，并且可能由单个河外“第一星”超新星丰富。与银河系中金属丰度最低的恒星不同，这颗恒星与我们的整体样本一样缺乏明显的碳增强。这种丰度差异和其他丰度差异证实，与早期银河系相比，河外早期大麦哲伦经历了不同的富集过程。因此，由最早的恒星驱动的早期元素生产似乎以依赖环境的方式进行。