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

早期宇宙尘埃颗粒的形成及其对观测的影响。

• 批准号: 13640229
• 负责人: KOZASA Takashi
• 金额: $ 1.15万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640229/
• 关键词: dust formation; supernoave; population III; dust; early universe; 星間物質; 宇宙論; presolar grains

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.

研究了 III 族超新星喷射物中的尘埃形成，不仅包括核心塌陷超新星 (CCSNe)，还研究了对不稳定超新星 (PISNE) 中喷射物中未混合和均匀混合的两种极端情况。 -核心。CCSNe和PISNe的计算结果总结如下：（1）未混合喷射物中凝结的各种颗粒物质反映了不同的颗粒物。喷射物中形成位置的元素组成；否则，均匀混合的喷射物中仅凝结有硅酸盐和氧化物颗粒 (2) 除镁硅酸盐、MgO、Si 外，每种颗粒的尺寸分布函数近似为对数正态分布。 ，以及非混合情况下的 FeS，以及两种情况下的 Al_2O_3 所有颗粒种类的尺寸分布函数通过指数为 -3.5 的幂律公式来近似。较大的半径，较小的为-2.5；交叉点的半径范围为 0.004 至 0.1μm，具体取决于原体质量 (3) 锁定在尘埃颗粒中的质量分数随着原体质量的增加而增加：2%。 CCSNe 的前体质量约为 5%，PISNe 的前体质量为 15%~30%，其前体质量范围为 140 至 260 M。基于计算出的尘埃为评价超新星爆发产生的尘埃颗粒量，采用闭箱模型，以初始质量函数、恒星形成速率和星际冲击尘埃破坏效率为参数，计算结果表明：粉尘量对粉尘破坏效率非常敏感。