Formation of Dust Grains in the Early Universe and its Effects on the Observations.

研究了III星族超新星喷发物中尘埃的形成，包括核心坍缩超新星（CCSNe）和对不稳定超新星（PISNE）。对于喷出物中的元素组成，考虑了两种极端情况；氦核内未混合和均匀混合的情况。CCSNe和PISNe的计算结果总结如下：(1)未混合喷射物中凝聚了多种颗粒，反映了喷射物中形成部位元素组成的差异；否则，只有硅酸盐和氧化物颗粒在均匀混合的喷射物中凝结。(2)除mg -硅酸盐、MgO、Si和FeS为未混合颗粒，Al_2O_3为未混合颗粒外，各颗粒粒径分布函数近似对数正态分布。所有颗粒种的粒径分布函数的求和近似为幂律公式，其指数为-3.5，大的为-3.5，小的为-2.5；交点半径范围为0.004 ~ 0.1μm，随前体质量的不同而不同。(3)锁在尘埃颗粒质量分数的增加而增加祖质量:CCSNe祖质量的2% ~ 5%,15% ~ 30%的PISNe祖质量范围从140到260 m .基于计算尘埃产生超新星,早期宇宙尘埃颗粒的数量是评估通过应用一个封闭的盒模型的初始质量函数、恒星形成率,和尘埃被星际冲击破坏效率作为参数。计算结果表明，粉尘量对粉尘破坏效率非常敏感。

Dust formation in the ejecta of population III supernovae including not only core-collapse supernoave (CCSNe) but also pair instability supernovae (PISNE) was investigated. Two extreme cases are considered for the elemental composition in the ejecta ; unmixed and uniformly mixed cases within He-core. The results of the calculations for CCSNe and PISNe are summarized as follows ; (1)A variety of grain species condense in the unmixed ejecta reflecting the diffeience in the elemental composition at the formation site in the ejecta ; otherwise only silicate and oxide grains condense in the uniformly mixed ejecta. (2)The size distribution function of each grain species is approximately log-normal, except for Mg-silicate, MgO,Si,and FeS in the unmixed case, and Al_2O_3 in both cases. The size distribution function summed up over all grain species is approximated by a power-law formula whose index is -3.5 for the larger radius and -2.5 for the smaller one ; the radius at the crossover point ranges from 0.004 to 0.1μm, depending on the progenitor mass. (3)The fraction of mass locked into dust grains increases with increasing the progenitor mass : 2%〜5% of the progenitor mass for CCSNe and 15%〜30% for PISNe whose progenitor mass ranges from 140 to 260 M. Based on the calculated dust yield from supernovae, the amount of dust grains in the early universe is evaluated by applying a closed box model where the initial mass function, star formation rate, and dust destruction efficiency by interstellar shock are taken as the parameters. The result of calculation shows that the amount of dust is very sensitive to the dust destruction efficiency.