Dust of comet 67P/Churyumov-Gerasimenko collected by Rosetta/MIDAS: classification and extension to the nanometer scale
Dust of comet 67P/Churyumov-Gerasimenko collected by Rosetta/MIDAS: classification and extension to the nanometer scale
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Rosetta/MIDAS 收集的 67P/Churyumov-Gerasimenko 彗星尘埃：分类和扩展到纳米尺度
DOI：
10.1051/0004-6361/201834851
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发表时间：
2019
影响因子：
6.5
通讯作者：
Iris Weber
中科院分区：
文献类型：
--
作者：
T. Mannel;Mark Bentley;P. Boakes;H. Jeszenszky;Pascale Ehrenfreund;Cécile Engrand;Christian Koeberl;A. Levasseur;J. Romstedt;R. Schmied;K. Torkar;Iris Weber
上下文彗星尘埃最小亚单位的性质包含了它们起源的信息，以及星子和行星形成的线索。与行星际尘埃颗粒或星尘使命期间收集的颗粒相比，罗塞塔使命期间在彗星67 P/Churyumov-Gerasimenko（67 P）的彗发中收集的尘埃提供了一种来源已知的变化最小的材料资源，其结构特性可用于进一步研究早期太阳系。
目标。对67 P彗星尘埃粒子的微米尺度形貌进行了分类，并将其结构分析扩展到纳米尺度。
方法.我们提出了一种新的方法，实现最高的空间分辨率的成像与MIDAS原子力显微镜上罗塞塔。分析分辨率低至8 nm的3D形貌图像，以确定纳米级颗粒的亚基尺寸。
结果可以确定三种形态类别：（i）尺寸大于约10 μm的易碎团聚颗粒，由微米级亚单位组成，这些亚单位本身可能是团聚体，并在颗粒表面显示出中等的堆积密度。(ii)一种易碎的团聚体，其尺寸约为几十微米，由微米级的亚单位组成，这些亚单位被认为是团聚体本身，并以分形维数低于2的结构排列。(iii)由数百纳米大小的亚基组成的微小微米级颗粒，其表面特征再次被认为是亚基。它们的微分尺寸分布遵循对数正态分布，平均值约为100 nm，标准偏差在20 nm和35 nm之间。
结论. MIDAS发现的尘埃颗粒的性质代表了Rosetta尘埃结果到微米和纳米尺度的扩展。所有微米级的颗粒都是由更小的亚单元组成的分级粉尘团块。最小确定表面特征的排列、外观和尺寸分布让人想起在南极多孔行星际尘埃颗粒中发现的那些特征。它们是67 P彗星中最小的直接探测到的亚单位。
Context. The properties of the smallest subunits of cometary dust contain information on their origin and clues to the formation of planetesimals and planets. Compared to interplanetary dust particles or particles collected during the Stardust mission, dust collected in the coma of comet 67P/Churyumov-Gerasimenko (67P) during the Rosetta mission provides a resource of minimally altered material with known origin whose structural properties can be used to further the investigation of the early solar system.
Aims. The cometary dust particle morphologies found at comet 67P on the micrometer scale are classified, and their structural analysis is extended to the nanometer scale.
Methods. We present a novel method for achieving the highest spatial resolution of imaging obtained with the MIDAS Atomic Force Microscope on board Rosetta. 3D topographic images with resolutions down to 8 nm were analyzed to determine the subunit sizes of particles on the nanometer scale.
Results. Three morphological classes can be determined: (i) fragile agglomerate particles of sizes larger than about 10 μm comprised of micrometer-sized subunits that may themselves be aggregates and show a moderate packing density on the surface of the particles. (ii) A fragile agglomerate with a size of about a few tens of micrometers comprised of micrometer-sized subunits that are suggested to be aggregates themselves and are arranged in a structure with a fractal dimension lower than two. (iii) Small micrometer-sized particles comprised of subunits in the size range of hundreds of nanometers that show surface features that are again suggested to represent subunits. Their differential size distributions follow a log-normal distribution with means of about 100 nm and standard deviations between 20 and 35 nm.
Conclusions. The properties of the dust particles found by MIDAS represent an extension of the dust results of Rosetta to the micro- and nanometer scale. All micrometer-sized particles are hierarchical dust agglomerates of smaller subunits. The arrangement, appearance, and size distribution of the smallest determined surface features are reminiscent of those found in chondritic porous interplanetary dust particles. They represent the smallest directly detected subunits of comet 67P.
影响因子：
4.8
作者：
Blum, Juergen;Gundlach, Bastian;Snodgrass, Colin
通讯作者：
Snodgrass, Colin