星系晕中的s过程：早期宇宙中自旋星的第五个特征？
The s-process in the Galactic halo: the fifth signature of spinstars in the early Universe?
摘要：
非常古老的晕星先前被发现显示出至少四种不同的丰度“异常”，快速旋转的大质量恒星（自旋星）模型可以成功地解释这些异常：N/O和C/O的上升，低12 C/13 C以及Be和B的原始演化。在这里，我们展示了这些恒星在早期宇宙中Sr和Ba富集的影响。我们研究了快速旋转大质量恒星的s过程产物是否可以解释金属丰度[Fe/H]<-2.5的晕星中[Sr/Ba]比值的扩展。利用化学非均匀模型计算了大质量恒星在星系晕中Sr和Ba的富集。我们的模型考虑到，第一次，spinstars的贡献。我们的模型（结合了快速旋转大质量恒星的r过程贡献和s过程）能够第一次再现在[Fe/H]<-2.5时观察到的[Sr/Ba]比散射。随着金属丰度的增加，恒星形成的随机性逐渐消失，这是由于爆炸和富集恒星的数量增加，因此预测的散射减小。我们的方案再次基于早期宇宙中自旋星的存在。非常古老的晕星以前被发现显示出至少四个其他丰度“异常”，大质量恒星的旋转模型可以成功地解释。我们的研究结果提供了快速旋转大质量恒星存在的第五个独立签名：宇宙在s过程元素中的早期富集。
英文摘要：
Very old halo stars were previously found to show at least four different abundance 'anomalies', which models of fast rotating massive stars (spinstars) can successfully account for: rise of N/O and C/O, low 12C/13C and a primary-like evolution of Be and B. Here we show the impact of these same stars in the enrichment of Sr and Ba in the early Universe. We study if the s-process production of fast rotating massive stars can offer an explanation for the observed spread in [Sr/Ba] ratio in halo stars with metallicity [Fe/H]< -2.5. By means of a chemical inhomogeneous model we compute the enrichment of Sr and Ba by massive stars in the Galactic halo. Our model takes into account, for the first time, the contribution of spinstars. Our model (combining an r-process contribution with a s-process from fast rotating massive stars) is able to reproduce for the first time the observed scatter in the [Sr/Ba] ratio at [Fe/H]< -2.5. Toward higher metallicities, the stochasticity of the star formation fades away due to the increasing number of exploding and enriching stars, and as a consequence the predicted scatter decreases. Our scenario is again based on the existence of spinstars in the early Universe. Very old halo stars were previously found to show at least four other abundance 'anomalies', which rotating models of massive stars can successfully account for. Our results provide a 5th independent signature of the existence of fast rotating massive stars: an early enrichment of the Universe in s-process elements.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
