The most massive and shortest-lived stars dominate the chemical evolution of the pre-galactic era. On the basis of numerical simulations, it has long been speculated that the mass of such first-generation stars was up to several hundred solar masses^1,2,3,4. The very massive first-generation stars with a mass range from 140 to 260 solar masses are predicted to enrich the early interstellar medium through pair-instability supernovae (PISNe)⁵. Decades of observational efforts, however, have not been able to uniquely identify the imprints of such very massive stars on the most metal-poor stars in the Milky Way^6,7. Here we report the chemical composition of a very metal-poor (VMP) star with extremely low sodium and cobalt abundances. The sodium with respect to iron in this star is more than two orders of magnitude lower than that of the Sun. This star exhibits very large abundance variance between the odd- and even-charge-number elements, such as sodium/magnesium and cobalt/nickel. Such peculiar odd–even effect, along with deficiencies of sodium and α elements, are consistent with the prediction of primordial pair-instability supernova (PISN) from stars more massive than 140 solar masses. This provides a clear chemical signature indicating the existence of very massive stars in the early universe.

质量最大、寿命最短的恒星主导着前银河时代的化学演化。根据数值模拟，长期以来人们推测此类第一代恒星的质量可达数百个太阳质量^1,2,3,4。质量范围为 140 至 260 个太阳质量的非常巨大的第一代恒星预计将通过不稳定对超新星 (PISNe) ⁵丰富早期星际介质。然而，数十年的观测努力未能唯一地识别出如此巨大的恒星在银河系中金属最贫乏的恒星上的印记^6,7。在这里，我们报告了一颗钠和钴丰度极低的极贫金属（VMP）恒星的化学成分。这颗恒星中的钠相对于铁的含量比太阳低两个数量级以上。这颗恒星在奇数和偶数电荷数元素（例如钠/镁和钴/镍）之间表现出非常大的丰度差异。这种奇特的奇偶效应，加上钠和 α 元素的缺乏，与质量超过 140 个太阳质量的恒星产生原初对不稳定超新星 (PISN) 的预测是一致的。这提供了清晰的化学特征，表明早期宇宙中存在非常大质量的恒星。