Growth and sedimentation of dust grains in the primordial solar nebula
Growth and sedimentation of dust grains in the primordial solar nebula
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DOI：
10.1016/0019-1035(81)90018-x
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发表时间：
1981-03
期刊：
影响因子：
3.2
通讯作者：
Y. Nakagawa;K. Nakazawa;C. Hayashi
中科院分区：
文献类型：
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作者：
Y. Nakagawa;K. Nakazawa;C. Hayashi
在太阳系的形成过程中，研究了地球轨道附近原始太阳星云中尘埃颗粒的生长和沉积过程。尘埃颗粒的生长方程，既下沉又处于热运动中，在10 - 12和106 g之间的宽质量范围内数值求解。星云中的任何湍流运动都被认为在沉积开始时已经衰减。数值模拟表明，由于生长和沉积的协同作用，生长和沉积的进行比Kusaka等（1970）的结果快，但与Safronov（1969）的估计一致;也就是说，在开始生长和沉积后约3 × 103年，一个由厘米大小的颗粒组成的尘埃层，形成于太阳星云的赤道。此外，在105年后，星云外层漂浮的尘埃颗粒的质量密度与沉降前相比，约为10− 5。根据这些结果，可以估计，在沉积开始后约5 × 103年，尘埃层由于重力不稳定性的开始而破裂。
Of the formation processes in the solar system, the process of growth and sedimentation of dust grains in the primordial solar nebula is investigated for a region near the Earth's orbit. The growth equation for dust grains, which are sinking as well as being in thermal motion, is solved numerically in the wide mass range between 10−12and 106g. Any turbulent motions in the nebula are assumed to have already decayed when the sedimentation begins. The numerical simulation shows that the growth and sedimentation proceed faster than was found by Kusaka et al. (1970) but in accordance with the estimate of Safronov (1969) owing to a cooperative interaction of the growth and the sedimentation; that is, at about 3 × 103years after the beginning of the growth and sedimentation a dust layer, composed of centimeter-sized grains, is formed at the equator of the solar nebula. Furthermore, the mass density of dust grains floating in the outer layers of the nebula is found to be of the order of 10−5after 105years compared with that before the sedimentation. From these results, it can be estimated that at about 5 × 103years after the beginning of sedimentation the dust layer breaks up owing to the onset of gravitational instability.