论文标题
早月的热演化
Thermal evolution of the early Moon
论文作者
论文摘要
在数值上已经模拟了月球的早期热演化，以了解影响加热的大小以及最初存储的吸积月亮的热能。本研究的主要目的是了解导致核心分化的过程的性质以及最初的对流岩浆海洋的产生和冷却。月亮的积聚是在巨大影响事件的100年的时间范围内开始的，早期太阳能系统大约300亿年。我们研究了行星过程对冲击场景的依赖性，积聚月球的初始平均温度以及在巨大冲击后一年内迅速超过Roche限制的原始人的大小。模拟表明，积聚的月球应在1600 K左右的最低初始平均温度。影响将提供额外的热能。月球的最初热状态取决于在罗氏极限内盛行的环境，这种环境经历了硅酸盐的广泛蒸发和重新调节的发作。在大多数模拟中产生了最初的对流岩浆深度超过1000 km，并且如果全球核心掩体分化，以防熔融金属通过散装硅酸盐的多孔流量熔化的渗透不是核心助理分化的主要模式。在多孔流的存在下，不能排除浅岩浆海洋的可能性。我们的模拟表明在$ 10^2 $ - $ 10^3 $年的月球积聚年内的核心隐形差异。对流岩浆海洋的大多数均在最初的$ 10^3 $ -10^4 $年内冷却以结晶。
The early thermal evolution of Moon has been numerically simulated to understand the magnitude of the impact induced heating and the initially stored thermal energy of the accreting Moonlets. The main objective of the present study is to understand the nature of processes leading to core-mantle differentiation and the production and cooling of the initial convective magma ocean. The accretion of Moon was commenced over a timescale of 100 years after the giant impact event around 30-100 million years in the early solar system. We studied the dependence of the planetary processes on the impact scenarios, the initial average temperature of the accreting moonlets and the size of the protoMoon that accreted rapidly beyond the Roche limit within the initial one year after the giant impact. The simulations indicate that the accreting Moonlets should have a minimum initial averaged temperature around 1600 K. The impacts would provide additional thermal energy. The initial thermal state of the moonlets depends upon the environment prevailing within the Roche limit that experienced episodes of extensive vaporization and re-condensation of silicates. The initial convective magma ocean of depth more than 1000 km is produced in the majority of simulations along with the global core-mantle differentiation in case the melt percolation of the molten metal through porous flow from bulk silicates was not the major mode of core-mantle differentiation. The possibility of shallow magma oceans cannot be ruled out in the presence of the porous flow. Our simulations indicate the core-mantle differentiation within the initial $10^2$-$10^3$ years of the Moon accretion. The majority of the convective magma ocean cooled down for crystallization within the initial $10^3$-$10^4$ years.
