太阳星云的演变

发布时间：2018-02-01 16:30

本文关键词： 太阳星云太阳系形成太阳系演化　出处：《吉林大学》2010年博士论文　论文类型：学位论文

【摘要】： 我们加入非均匀粘滞以及从分子云核坍缩来的质量流入研究太阳星云的形成、结构、和演变。计算中应用了被接受的最新的非均匀粘滞,还有从恒星形成理论中得出的合适的质量流入。在粘滞的计算中,我们考虑了磁转动不稳的效应。星云面密度和其它物理量的径向分布显著不同于以前的星云模型,那些模型或者没有考虑非均匀粘滞,或者没有加入质量流入。我们发现,由于云核是从内向外开始坍缩,星云从内边界处开始形成,然后由于粘滞向外扩展。与均匀粘滞情况不同,面密度不是半径的单调函数。由于非均匀粘滞的存在,在1.5AU附近有面密度的极小值出现。在坍缩结束之前,除暂时最小值的移动以及星云的逐渐扩展之外,面密度维持它的大体形态,原因是从坍缩来的质量供给抵消了被吸入原太阳的质量损失,并提供星云扩展所需的质量。我们的计算证实了Jin的那个早期论点,认为非均匀粘滞可以解释类木行星之间的质量差别和气体组成差别。我们的星云计算结果显示,在半径大于0.3AU处,星云温度低于1200K。即使是在星云内部,从分子云中来的难熔物质也能存活,难熔聚合物能形成。我们研究发现,星云面密度是非单调的,在火星区域有一极小值。这自然与行星质量分布符合,尤其是火星处的质量下降。
[Abstract]:We add nonuniform viscosity and mass flow from the collapse of molecular cloud nuclei to study the formation, structure, and evolution of the solar nebula. There is also a suitable mass inflow derived from star formation theory. In the calculation of viscosity, we take into account the effect of magnetic instability. The radial distribution of nebula surface density and other physical quantities is significantly different from previous nebula models. Those models either did not take into account inhomogeneous viscosity or did not add mass inflow. We found that because the cloud core began to collapse from the inside out, the nebula began to form at the inner boundary. Then, due to the outward propagation of the viscosity, the surface density is not a monotone function of the radius, unlike the uniform viscosity. Due to the existence of non-uniform viscosity, there is a minimum value of the surface density near 1.5 AU. Before the collapse ends, In addition to the movement of the temporary minimum and the gradual expansion of the nebula, the surface density maintains its general shape because the mass supply from the collapse offsets the loss of mass absorbed into the original sun. And provide the mass needed to expand the nebula. Our calculations confirm Jin's earlier argument that nonuniform viscosity can explain the difference in mass and gas composition between wood-like planets. Our nebula calculations show that, At a radius greater than 0.3 AU, the temperature of the nebula is below 1200 kg. even within the nebula, refractory matter from molecular clouds can survive and refractory polymers can form. We found that the density of the nebula is nonmonotonic. There is a minimum in the Martian region. This naturally corresponds to the mass distribution of the planet, especially the mass decline on Mars.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2010
【分类号】：P181

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