Al-26和太阳系从沃尔夫-拉叶风污染的分子云形成
Al-26 and the formation of the Solar System from a molecular cloud contaminated by Wolf-Rayet winds
摘要：
与以前的工作一致，我们表明，在早期太阳系中存在的短寿命放射性核素Al-26是不太可能的（<2%的先验概率）是直接引入的超新星喷出物到气体盘在第二类阶段的原太阳演化的结果。我们还表明，任何Bondi-Hoyle吸积的污染残留气体从出生的星团作出了微不足道的贡献，原始的Al-26库存的太阳系。这些结果是一致的氧同位素的签名预期与任何后期引入的超新星喷出物到原行星盘的情况下。相反，Al-26存在于太阳系最古老的固体（富含钙铝的包裹体或CAIs）中，并且其明显的均匀分布与推断的典型Al-26/Al-27比为（4.5-5）E-5，支持Al-26继承自母巨分子云。我们认为，这种放射性核素起源于前一代的大质量恒星，形成在同一主机分子云作为太阳和污染的沃尔夫-拉叶风云。我们计算了银河系分布的Al-26/Al-27的比例，从这样的污染使用已建立的嵌入式集群质量和恒星初始质量函数，公布的核合成产量从风的大质量恒星，并通过假设快速和均匀的混合到云。虽然我们的模型预测，大多数恒星系统不包含来自大质量恒星的Al-26，并且Al-26/Al-27比值达到或超过正则太阳系值的先验概率仅为~ 6%，但非零值分布的最大值接近正则比值。
英文摘要：
In agreement with previous work, we show that the presence of the short-lived radionuclide Al-26 in the early Solar System was unlikely (<2% a priori probability) to be the result of direct introduction of supernova ejecta into the gaseous disk during the Class II stage of protosolar evolution. We also show that any Bondi-Hoyle accretion of contaminated residual gas from the natal star cluster made a negligible contribution to the primordial Al-26 inventory of the Solar System. These results are consistent with the absence of the oxygen isotopic signature expected with any late introduction of supernova ejecta into the protoplanetary disk. Instead, the presence of Al-26 in the oldest Solar System solids (calcium-aluminum-rich inclusions or CAIs) and its apparent uniform distribution with the inferred canonical Al-26/Al-27 ratio of (4.5-5)E-5 support the inheritance of Al-26 from the parent giant molecular cloud. We propose that this radionuclide originated in a prior generation of massive stars that formed in the same host molecular cloud as the Sun and contaminated that cloud by Wolf-Rayet winds. We calculated the Galactic distribution of Al-26/Al-27 ratios that arise from such contamination using the established embedded cluster mass and stellar initial mass functions, published nucleosynthetic yields from the winds of massive stars, and by assuming rapid and uniform mixing into the cloud. Although our model predicts that the majority of stellar systems contain no Al-26 from massive stars, and that the a priori probability that the Al-26/Al-27 ratio will reach or exceed the canonical Solar System value is only ~6%, the maximum in the distribution of non-zero values is close to the canonical ratio.
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。
