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Reevalution of Lunar Heat Flow Experiment: (Construction of a LUnar Thermal Model using Lunar Prospector Data)

月球热流实验的重新评估：（利用月球勘探者数据构建月球热模型）

基本信息

批准号：
12640413
负责人：
MIZUTANI Hitoshi
金额：
$ 2.43万
依托单位：
The Institute of Space and Astronautical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640413/
关键词：
moon heat flow Prospector Clementine lunar crust gravity lunar toppography finite element method

项目摘要

Since lunar heat flow provides us with a unique means to estimate the bulk abundance of refractory elements in the moon, it is very important to re-assess the heat flow data obtained in the Apollo 15 and 17 missions, in terms of new global data obtained by recent lunar missions. In this paper, we analyze the Apollo heat flow data combining the topography, gravity field, and Thorium abundance data by Prospector mission and Clementine mission.First we investigated the effect of topography variation and mega-regolith thickness variation on the measured heat flow, using a finite element method. This effect is believed to be very significant on Apollo heat flow values, because the measurements at the both Apollo 15 and 17 sites are made near the boundary of lunar mare and highland where the topography and mega-regolith thickness changes drastically. The result of the numerical experiments show that the observed heat flow values at Apollo 15 and 17 sites are 10 to 20 % larger than the representative values of those sites.We construct two crustal-structure models by analyzing the topography and gravity field data one model (thick crust model) has a mean crustal thickness of 61 kin, and the other model (thin crust model) has a mean crustal thickness of 48 km. Combing these crustal models with Prospector's Thorium abundance map, we calculated the surface heat flow expected from the crustal models. Comparison of the theoretical heat flow values with the reevaluated Apollo heat flow values indicates that the bulk U abundance in the Moon is 20 to 30 ppb which is more or less similar to that of the upper mantle of the Earth. This suggests that refractory elements in the Moon are not so much enriched as those proposed by previous many workers on chemistry of returned lunar samples. The conclusion has significant influence of our view of the lunar origin.

由于月球热流为我们提供了一种独特的方法来估计月球中耐火元素的丰度，因此根据最近月球任务获得的新的全球数据，重新评估阿波罗15号和17号任务中获得的热流数据非常重要。本文结合Prospector使命和Clementine使命的地形、重力场和钍丰度数据，分析了阿波罗热流数据。首先，利用有限元方法研究了地形变化和巨风化层厚度变化对热流测量的影响。这种影响被认为对阿波罗热流值非常重要，因为阿波罗15号和17号的测量都是在月海和高地的边界附近进行的，那里的地形和大风化层厚度变化剧烈。数值试验结果表明，阿波罗15号和阿波罗17号观测点的热流值比典型观测点的热流值偏大10%~20%，通过对观测点的地形和重力场资料的分析，建立了两个地壳结构模型厚地壳模型的地壳平均厚度为61 km，薄地壳模型的地壳平均厚度为48 km。结合这些地壳模型与探矿者的钍丰度图，我们计算了地表热流预计从地壳模型。将理论热流值与重新估算的阿波罗热流值进行比较表明，月球中铀的丰度为20~30ppb，与地球上地幔的丰度相近。这表明月球中的难熔元素并不像以前许多工作人员在返回月球样品的化学方面所提出的那样丰富。这一结论对我们对月球起源的认识有重要影响。

项目成果

期刊论文数量（25）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

吉田信介, 宮崎ゆか, 田中智, 宝来帰一, 水谷仁, 藤村彰夫, 平井研一: "LUNAR-Aペネトレータによる月熱流量計測 : 非定常解析による月熱流量の推定"2002年度合同学会予稿集. P036-P003 (2002)

Shinsuke Yoshida、Yuka Miyazaki、Satoshi Tanaka、Kiichi Horai、Hitoshi Mizutani、Akio Fujimura、Kenichi Hirai：“使用LUNAR-A穿透器测量月球热流：使用非定常分析估计月球热流”2002年联合学术会议论文集。 P036-P003 (2002)