EUVE photometric observations of the Moon
EUVE photometric observations of the Moon
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EUVE 月球光度观测
DOI：
10.1029/93gl03290
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发表时间：
1994
影响因子：
5.2
通讯作者：
S. Bowyer
中科院分区：
文献类型：
--
作者：
G. Gladstone;J. McDonald;W. Boyd;S. Bowyer
在全天巡天期间，极紫外探测器（EUVE）卫星在第一季度和最后一季度对月球进行了多次观测，并在1992年12月10日月食之后立即进行了一次观测。我们在这里提出的一部分数据，在极端紫外线（EUV）的月球图像和衍生几何的照片的形式。对月球的远紫外观测具有相当大的意义，因为据推测，月球的极紫外辐射可能主要是L壳层和M壳层的X射线荧光，因此可以提供对表面元素丰度的有用诊断。从EUVE光度计数据中，我们得到在150-240 A、400-580 A和550-650 A的波长间隔内，平均几何折射率分别为0.15%（± 0.03%）、3.1%（± 0.3%）和3.5%（±0.3%）。列出的标准偏差仅来自光子计数统计，不包括由假设的太阳EUV通量和零相位角校正引起的不确定性。在75-180埃波长范围内，获得了0.13%的上限几何色散。此外，使用以前发表的ROSAT数据，我们估计月球的几何反射率为0.014%（±0.002%）的波长间隔50-80 A。这些EUV反射率（和先前公布的远紫外反射率）与SiO2和Al 2 O3的比例反射率很好地拟合。在EUVE光度计的波长范围内，观测到的月球亮度似乎与反射的太阳光而不是X射线荧光基本一致。然而，由于L壳层和M壳层的荧光信号预计只会由少量的发射线携带，因此需要更高光谱分辨率的EUV观测（105 A）来确定它们对月球EUV光谱的确切贡献（如果有的话）。
During its all-sky survey, the Extreme Ultiaviolet Explorer (EUVE) satellite observed the Moon several times at first and last quarters, and once immediately following the Dec. 10, 1992 lunar eclipse. We present here a portion of this data, in the form of extreme-ultraviolet (EUV) images of the Moon and derived geometric albedos. Extreme ultraviolet observations of the Moon are of considerable interest, since it has been speculated that lunar EUV emissions may be dominated by L- and M-shell X-ray fluorescence and may thus provide a useful diagnostic of surface elemental abundances. From the EUVE photometer data we obtain average geometric albedos of 0.15% (±0.03%), 3.1% (±0.3%), and 3.5% (±0.3%), over wavelength intervals of 150–240 A, 400–580 A, and 550–650 A, respectively. The standard deviations listed result from photon counting statistics only—uncertainties arising from the assumed solar EUV flux and the correction to zero phase angle are not included. An upper limit geometric albedo of 0.13% is obtained for the wave-length interval 75–180 A. Also, using previously published ROSAT data, we estimate a lunar geometric albedo of 0.014% (±0.002%) over the wavelength interval 50–80 A. These EUV albedos (and previously published far-ultraviolet albedos) are well fit by the scaled reflectivities of SiO2 and Al2O3. Over the wavelength ranges of the EUVE photometers, the observed brightness of the Moon seems to be largely consistent with reflected sunlight rather than X-ray fluorescence. Since the L- and M-shell fluorescence signal is expected to be carried by only small number of emission lines, however, it will require EUV observations of higher spectral resolution (≲5 A) to determine their exact contribution, if any, to the lunar EUV spectrum.