GLOBAL DUST CIRCULATION IN THE PROTO-PLANETARY DISK

一般认为，太阳系中行星和小行星的体相化学组成相似，但太阳丰度比略有不同。整体成分的变化可能是由原行星盘周围的尘埃全球循环造成的。尘埃从盘的外缘螺旋进入原太阳，部分尘埃从盘的内缘发射到外缘。在本研究中，我们对陨石进行了化学分析，并对原行星盘中的电磁效应、动力学效应和化学反应网络进行了数值模拟。结果表明：（1）太阳系中观测到的氧同位素异常起源于母分子云，是紫外光照射下一氧化碳的自屏蔽效应所致;（2）分子云中的氧同位素分馏分离为星际气体和冰相。行星的氧同位素组成主要取决于原行星盘中尘埃的富集因子和冰的蒸发。4.数值模拟表明，原行星盘中的气尘比控制着气体行星绕中心星星的运动轨迹和质量。计算结果与天文观测中太阳系外行星的概率相吻合。这一结论表明，恒星形成过程决定了原行星盘的数量，而星星周围行星的形成则受盘内气尘比的控制。5.对星际等离子体电磁涡旋的性质进行了数值模拟。电子的惯性效应对涡旋的演化有重要影响。较大尺度的涡旋立即被细分为较小尺度的涡旋。这一过程表明，物质混合在空间中的演变比以往任何时候都要迅速。

It is believed that bulk chemical compositions among planets and asteroids in the solar system is similar but slightly different from the solar abundance ratios one another. The variations of the bulk composition may result from a global circulation of dusts around the proto-planetary disk. The dusts spiral into the proto-sun from outer edge of the disk and some of them launched from the inner edge of the disk to the outer-edge. In this study, we made chemical analyses of meteorites and numerical simulations of electro-magnetic effects, dynamic effects and chemical reaction network estimated in the proto-planetary disk. We may conclude the subjects as follows :1.Oxygen isotopic anomaly observed in the solar system was originated in the parent molecular cloud by a self-shielding effect of carbon monoxides by ultra-violet light irradiation.2.The oxygen isotopic fractionation in the molecular cloud was separated into interstellar gas and ice phases. Differences of dynamics and chemistry in the disk introduced the anomaly of oxygen isotopes in the solar system.3.oxygen isotopic compositions of planets were mainly determined by enrichment factor of dusts and evaporation of ice in a proto-planetary disk.4.A numerical simulation suggests that trajectory around a central star and the mass of gas planets were controlled by gas-dust ratios in a proto-planetary disk. The results correspond to probabilities of extra-solar planets by astronomical observations. This conclusion suggests that amounts of proto-planetary disk are determined by star-formation process, but the planetary formation around the star is controlled by the gas-dust ratio in the disk.5.Nature of electro-magneto vortex of interstellar plasma was simulated numerically. Inertia effects of electrons are important to the vortex evolution. Larger scale vortex is immediately fractionized to smaller scale ones. This process suggests that material mixing is promptly evolved in the space than ever thought.