STELLAR YIELDS OF ROTATING FIRST STARS. I. YIELDS OF WEAK SUPERNOVAE AND ABUNDANCES OF CARBON-ENHANCED HYPER-METAL-POOR STARS

We perform a stellar evolution simulation of first stars and calculate stellar yields from the first supernovae. The initial masses are taken from 12 to 140 M☉ to cover the whole range of core–collapse supernova progenitors, and stellar rotation is included, which results in efficient internal mixing. A weak explosion is assumed in supernova yield calculations, thus only outer distributed matter, which is not affected by the explosive nucleosynthesis, is ejected in the models. We show that the initial mass and the rotation affect the explosion yield. All the weak explosion models have abundances of [C/O] larger than unity. Stellar yields from massive progenitors of >40–60 M☉ show enhancement of Mg and Si. Rotating models yield abundant Na and Al, and Ca is synthesized in nonrotating heavy massive models of >80 M☉. We fit the stellar yields to the three most iron-deficient stars and constrain the initial parameters of the mother progenitor stars. The abundance pattern in SMSS 0313−6708 is well explained by 50–80 M☉ nonrotating models, rotating 30–40 M☉ models well fit the abundance of HE 0107–5240, and both nonrotating and rotating 15–40 M☉ models explain HE 1327–2326. The presented analysis will be applicable to other carbon-enhanced hyper-metal-poor stars observed in the future. The abundance analyses will give valuable information about the characteristics of the first stars.

我们对第一代恒星进行了恒星演化模拟，并计算了第一代超新星的恒星产量。初始质量取值从12到140倍太阳质量，以涵盖核心坍缩超新星前身星的整个范围，并且考虑了恒星自转，这导致了有效的内部混合。在超新星产量计算中假设是弱爆炸，因此在模型中只有不受爆炸核合成影响的外部物质被抛射出去。我们表明初始质量和自转影响爆炸产量。所有弱爆炸模型的[C/O]丰度都大于1。质量大于40 - 60倍太阳质量的大质量前身星的恒星产量显示出镁和硅的增加。自转模型产生大量的钠和铝，钙在质量大于80倍太阳质量的非自转大质量模型中合成。我们将恒星产量与三颗最缺铁的恒星进行拟合，并对母前身星的初始参数进行约束。SMSS 0313 - 6708的丰度模式可以由50 - 80倍太阳质量的非自转模型很好地解释，自转的30 - 40倍太阳质量模型很好地符合HE 0107 - 5240的丰度，并且非自转和自转的15 - 40倍太阳质量模型都能解释HE 1327 - 2326。所提出的分析将适用于未来观测到的其他碳增超贫金属星。丰度分析将提供有关第一代恒星特征的有价值信息。