标题： AKARI/IRC观测的黄道发射的中红外光谱 显示英文标题

标题： Mid-infrared spectroscopy of zodiacal emission with AKARI/IRC

摘要： 星际尘埃（IPD）被认为是由小行星和彗星提供的。 IPD 的颗粒特性可以为我们提供原太阳系环境的信息，并且可以通过在黄道光发射光谱中看到的约 10 $\mu$m 处硅酸盐特征的形状来追溯。 我们分析了来自 AKARI 卫星红外相机的各个天空方向的黄道光发射的中红外狭缝光谱数据。 在减去仪器伪影引起的污染后，我们成功获得了高信噪比光谱，并确定了所有天空方向在 9 至 12 $\mu$m 范围内超额发射特征的详细形状。 根据所有方向平均特征形状与候选矿物吸收系数之间的比较，发现 IPD 通常包括小的硅酸盐晶体，特别是顽火辉石颗粒。 我们还发现了不同天空方向特征形状和相关颗粒性质的变化。 通过研究特征形状与尘带亮度贡献之间的相关性，发现尘带中的 IPD 的粒度频率分布似乎偏向于大颗粒，并显示出含水矿物的迹象。 更高黄道纬度的光谱显示超额更强，这表明更高黄道纬度视线内的小颗粒比例增加。 如果关注详细特征形状对黄道纬度的依赖关系，发现在较高纬度的 IPD 对于小的非晶态颗粒具有较低的橄榄石/辉石比值。 不同天空方向下 IPD 的矿物成分变化可能意味着来自不同类型母体的不同 IPD 特性，因为 IPD 的空间分布取决于母体类型。 显示英文摘要

摘要： Interplanetary dust (IPD) is thought to be recently supplied from asteroids and comets. Grain properties of the IPD can give us the information about the environment in the proto-solar system, and can be traced from the shapes of silicate features around 10 $\mu$m seen in the zodiacal emission spectra. We analyzed mid-IR slit-spectroscopic data of the zodiacal emission in various sky directions obtained with the Infrared Camera on board AKARI satellite. After we subtracted the contamination due to instrumental artifacts, we have successfully obtained high S/N spectra and have determined detailed shapes of excess emission features in the 9 -- 12 $\mu$m range in all the sky directions. According to a comparison between the feature shapes averaged over all directions and the absorption coefficients of candidate minerals, the IPD was found to typically include small silicate crystals, especially enstatite grains. We also found the variations in the feature shapes and the related grain properties among the different sky directions. From investigations of the correlation between feature shapes and the brightness contributions from dust bands, the IPD in dust bands seems to have the size frequency distribution biased toward large grains and show the indication of hydrated minerals. The spectra at higher ecliptic latitude showed a stronger excess, which indicates an increase in the fraction of small grains included in the line of sight at higher ecliptic latitudes. If we focus on the dependence of detailed feature shapes on ecliptic latitudes, the IPD at higher latitudes was found to have a lower olivine/pyroxene ratio for small amorphous grains. The variation of the mineral composition of the IPD in different sky directions may imply different properties of the IPD from different types of parent bodies, because the spatial distribution of the IPD depends on the type of the parent body.