The composition of 433 Eros: A mineralogical—chemical synthesis
The composition of 433 Eros: A mineralogical—chemical synthesis
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433 Eros 的成分：矿物学-化学合成
DOI：
10.1111/j.1945-5100.2001.tb01855.x
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发表时间：
2001
影响因子：
2.2
通讯作者：
J. Veverka
中科院分区：
文献类型：
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作者：
T. Mccoy;T. Burbine;L. McFadden;R. Starr;M. Gaffey;L. Nittler;L. Evans;N. Izenberg;P. Lucey;J. Trombka;J. Bell;B. Clark;P. Clark;S. Squyres;C. Chapman;W. Boynton;J. Veverka
摘要：近地小行星交会（near）任务携带了x射线/伽马射线光谱仪和多光谱成像仪/近红外光谱仪仪器包，分别提供了目标小行星433 Eros的化学和矿物学的补充信息。这两个数据集的综合提供了任何一个数据集都无法获得的信息，包括非基性硅酸盐、金属和硫化物矿物的丰度。我们使用了四种技术来综合这些数据集。研究两个数据集重叠特征的维恩图表明，与爱神星433最匹配的是一颗在小行星表面发生改变的普通球粒陨石，或者可能是一颗从矿物学上与这些球粒陨石相似的物质中提取的原始无球粒陨石。标准化的元素分布排除了富FeO辉石，并表明x射线和伽马射线数据可以通过包含不同数量的金属而与普通硅酸盐矿物学相一致。由于氧丰度的不确定性和钠丰度缺乏任何限制，规范矿物学不能应用于这些数据集。同时解决矿物丰度的矩阵反演对x射线衍生的体组成得到了合理的结果，但似乎证实了矿物组成和正辉/斜辉比之间的不一致。在综合这些多个数据集时，似乎不可能有唯一的解决方案。未来的任务包括一个全面表征风化层分布和样本返回的着陆器，将解决合成近地数据所面临的各种问题。
Abstract— The near‐Earth asteroid rendezvous (NEAR) mission carried x‐ray/gamma‐ray spectrometers and multi‐spectral imager/near‐infrared spectrometer instrument packages which gave complementary information on the chemistry and mineralogy, respectively, of the target asteroid 433 Eros. Synthesis of these two data sets provides information not available from either alone, including the abundance of non‐mafic silicates, metal and sulfide minerals. We have utilized four techniques to synthesize these data sets. Venn diagrams, which examine overlapping features in two data sets, suggest that the best match for 433 Eros is an ordinary chondrite, altered at the surface of the asteroid, or perhaps a primitive achondrite derived from material mineralogically similar to these chondrites. Normalized element distributions preclude FeO‐rich pyroxenes and suggest that the x‐ray and gamma‐ray data can be reconciled with a common silicate mineralogy by inclusion of varying amounts of metal. Normative mineralogy cannot be applied to these data sets owing to uncertainties in oxygen abundance and lack of any constraints on the abundance of sodium. Matrix inversion for simultaneous solution of mineral abundances yields reasonable results for the x‐ray‐derived bulk composition, but seems to confirm the inconsistency between mineral compositions and orthopyroxene/clinopyroxene ratios. A unique solution does not seem possible in synthesizing these multiple data sets. Future missions including a lander to fully characterize regolith distribution and sample return would resolve the types of problems faced in synthesizing the NEAR data.
K. Tomeoka：“Yamamoto-791717 CO 碳质球粒陨石中富含 Na 的 Ca-Al 包裹体”陨石学。
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