Experimental study of condensation process of minerals in the primodial solar nebula.

原始太阳星云矿物凝结过程的实验研究。

基本信息

批准号：
61540590
负责人：
TSUCHIYAMA Akira
金额：
$ 1.41万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61540590/
关键词：
Primodial solar nebula Condensation Silicate minerals Solid planets Meteorites Ostwald ripening Vacuum furnace for vaporization and condensation Reproduction experiments of condensation Olivine VLS mechanism Whiskers Heterogeneous nu

项目摘要

Condensation of mineral grains from gas at high temperatures took place in the primodial solar nebula, and solid planets and meteorites were formed by accretion of these grains. In the present research project, the following experiments on condensation were carried out to understand the primodial solar nebula; (1) condensation experiments of forsterite, (2) reaction experiments between olivine and Si-rich gas, and (3) coarsening experiments of olivine.(1) A new vacuum furnace, in which silicates are volatilized by heating and condensation takes place from the gas, was specially designed. By using this furnace, experiments were carried out in the system Mg_2SiO_4-H_2, which mimics the solar composition. Conditions for the condensation were determined, and it was concluded that the condensation is mainly controlled by temperature and forsterite whiskers can grow by the VLS mechanism. Condensates in the system MgSIO_3-H_2 produced at Carnegie Institution, U.S.A. were also examined. It was concluded that heterogeneous nucleation would play an important role in the condensation process.(2) Reaction between condensates and residual gas is another important process during the condensation. Preliminary experiments on reaction between olivine and Si-rich gas indicate that the reaction hardly took place for olivine crystals larger than the order of 1 um.(3) The crystal size is one of the most important factor not only for the reaction kinetics but also for solid-gas fractionation. Preliminary experiments using forsterite crystals indicate that coarsening due to Ostwald ripening was not effective even in slowly cooled nebula.

在原始的太阳星云中发生了高温下气体矿物晶粒的凝结，并通过这些晶粒的积聚形成固体行星和陨石。在本研究项目中，进行了以下凝结实验，以了解原始太阳星云。（1）橄榄石和富含Si的气体之间的脱晶石实验，（2）橄榄石的变形实验。（1）一种新的真空熔炉，在该真空熔炉中，硅酸盐通过天然气的加热和冷凝物挥发了硅酸盐，是专门设计的。通过使用此炉子，在系统MG_2SIO_4-H_2中进行了实验，该系统模仿太阳能组成。确定冷凝的条件，得出的结论是，凝结主要由温度控制，而玻璃石晶须可以通过VLS机制生长。还检查了在美国卡内基机构生产的系统中MGSIO_3-H_2的冷凝物。结论是，异质成核将在冷凝过程中起重要作用。（2）冷凝水与残留气体之间的反应是冷凝过程中的另一个重要过程。关于橄榄石和富含Si的气体反应的初步实验表明，对于大于1 um的橄榄石晶体几乎没有进行反应。（3）晶体尺寸不仅是反应动力学的最重要因素之一，而且是固体GAS分裂的最重要因素之一。使用脚石晶体的初步实验表明，即使在缓慢冷却的星云中，由于奥斯特瓦尔德成熟而导致的变形也不有效。