Blowing in the wind: III. Accretion of dust rims by chondrule-sized particles in a turbulent protoplanetary nebula
Blowing in the wind: III. Accretion of dust rims by chondrule-sized particles in a turbulent protoplanetary nebula
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风中飘扬：三．
DOI：
10.1016/j.icarus.2003.12.008
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发表时间：
2004
期刊：
影响因子：
3.2
通讯作者：
J. Cuzzi
中科院分区：
文献类型：
--
作者：
J. Cuzzi
原始陨石的结构主要由微小但宏观的颗粒组成——球粒、难熔矿物内含物（CAI）、金属颗粒等。这些颗粒的一个有趣的方面是，它们通常被紧密附着的细粒尘埃边缘包围，这些尘埃似乎已“附着”到固体矿物核心上。一颗陨石的边缘厚度各不相同，但边缘的厚度和核心的大小之间似乎存在比例关系。我们利用最近导出的弱湍流星云中球粒和 CAI 大小的粒子的绝对和相对速度的解析表达式（Cuzzi 和 Hogan，2003 年，本系列论文 I）来评估球粒到 CAI 大小范围内的粒子对细粒吸积尘埃边缘的获取。我们将这些预测与陨石观测进行比较，并展示如何在湍流星云背景下轻松理解球粒和类似大小物体上相当致密的尘埃边缘的存在。我们估计形成这样的边缘所需的时间在 102-103 年范围内。为了强烈限制这些物体的环境和历史，需要对尘埃球粒球粒的边缘和核心直径之间的相关性进行更多观察。
The fabric of primitive meteorites is dominated by small but macroscopic particles—chondrules, refractory mineral inclusions (CAIs), metal grains, and their like. One interesting aspect of these particles is that they are often surrounded by well-attached rims of fine-grained dust which appear to have been “accreted” onto solid mineral cores. The rim thickness varies from one meteorite to another, but there seems to be a proportionality between the thickness of the rim and the size of the core. We make use of recently derived analytical expressions for absolute and relative velocities of chondrule-and-CAI-sized particles in a weakly turbulent nebula (Cuzzi and Hogan, 2003, paper I of this series) to assess the acquisition of fine-grained accretionary dust rims by particles in the chondrule-to-CAI size range. We compare these predictions with meteoritic observations, and show how the existence of fairly compact dust rims on chondrules and similar size objects can be easily understood within the turbulent nebula context. We estimate the time needed to accrete such rims to be in the 102–103year range. More observations of the form of the correlation between rim and core diameter in dust-rimmed chondrules are needed in order to strongly constrain the environment and history of these objects.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell