Settling and growth of dust particles in a laminar phase of a low-mass solar nebula
Settling and growth of dust particles in a laminar phase of a low-mass solar nebula
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DOI：
10.1016/0019-1035(86)90121-1
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发表时间：
1986-09
期刊：
影响因子：
3.2
通讯作者：
Y. Nakagawa;M. Sekiya;C. Hayashi
中科院分区：
文献类型：
--
作者：
Y. Nakagawa;M. Sekiya;C. Hayashi
它被认为是一些垂直对流以及可能的湍流在太阳星云的早期阶段很快结束，由于尘埃粒子的快速增长的尘埃不透明度的温度依赖性的减小。我们重新研究尘埃粒子的沉降和生长在随后的层流阶段的太阳星云的细节，治疗尘埃层作为一个双组分流体组成的尘埃和气体。我们得到的解决路径，增长的大小，和解决时间的解析表达式。沉降过程分为两个阶段，即，一个早期的气体为主的阶段和一个后期的灰尘为主的阶段。到目前为止，只有前一个阶段，其中粒子路径最终从垂直转向径向，已被调查。在后一阶段，尘埃颗粒拖曳气体，而不是气体拖曳尘埃颗粒。因此，粒子路径从径向变为垂直。尘埃粒子在径向扫掠阶段增长最明显和最快。在地球、木星和海王星带，尘埃层引力不稳定开始时尘埃粒子的最终半径分别为20、5.9和0.60厘米。这些值比S. J. Weidenschilling [1980，Icarus 44，172-189]和Y. Nakagawa等人[1981，Icarus 45，517-528]。上述三个带的总沉降时间分别为1.9 × 103、4.6 × 103和2.8 × 104年。这比以前的研究所获得的结果要小一些。大部分沉降时间花在早期垂直沉降阶段。
It is considered that some vertical convection as well as possible turbulence in an early phase of solar nebula soon terminates owing to diminution of the temperature dependence of dust opacity due to rapid growth of dust particles. We reexamine settling and growth of dust particles in the subsequent laminar phase of the solar nebula in detail, treating a dust layer as a two-component fluid composed of the dust and the gas. We obtain analytic expressions for the settling path, the growing size, and the settling time. The settling process is divided into two phases, i.e., an early gas-dominant phase and a later dust-dominant phase. So far, only the former phase, where the particle path finally turns from vertical to radial, has been investigated. In the latter phase, dust particles drag the gas, rather than the gas does dust particles. Consequently, the particle path turns from radial to vertical. Dust particles grow most appreciably and rapidly in a radially sweeping phase. The final radii of dust particles at the onset of gravitational instability of the dust layer are 20, 5.9, and 0.60 cm in the Earth's, Jupiter's, and Neptune's zones, respectively. These values are much smaller than those obtained previously by S.J. Weidenschilling [1980, Icarus44, 172–189] and Y. Nakagawa et al. [1981, Icarus45, 517–528]. The total settling times are 1.9 × 103, 4.6 × 103, and 2.8 × 104years in the above-mentioned three zones, respectively. These are somewhat smaller than those obtained by the previous studies. Most of the settling time is spent in the early vertically settling phase.