木卫三的表面组成和性质：用近红外成像光谱仪SINFONI/VLT/ESO进行的地面观测的更新
Surface composition and properties of Ganymede: Updates from ground-based observations with the near-infrared imaging spectrometer SINFONI/VLT/ESO
摘要：
木卫三的表面表现出巨大的地质多样性，古老的黑暗地形，通过表面成分表示，已知主要由两种成分组成：H2O冰和一种身份不明的变暗剂。在本文中，新的调查组成木卫三的表面在全球范围内。分析来自高光谱分辨率数据集的线性光谱建模，获得与近红外地基积分场光谱仪SINFONI的VLT。我们发现，Oren-Nayar（1994）的模型，概括了粗糙表面的朗伯定律，产生良好的光度校正。建模证实，木卫三的表面成分主要是H2O冰，主要是结晶，以及变暗剂，但它也强调了二级物种的必要性，以更好地适应测量：硫酸水合物和盐。纬度梯度和半球形的二分法是观察到的最强的空间图案的变暗剂，水冰，和硫酸：变暗剂是主要的化合物在赤道和中纬度地区，特别是在后半球，而水冰和硫酸主要位于高纬度地区和领先的半球。这种反相关性可能是木星磁层中成分轰击的结果，这些成分在高纬度地区更为强烈。此外，建模证实，极冠富含小，新鲜，H2O-冰粒，而赤道地区由较大的颗粒。最后，盐的空间分布既不与木星的磁层轰击，也没有陨石坑。这些物种大多在黑暗地区周围明亮的沟槽地形上被发现。冰壳中上升流的冻结等内生过程可以解释这种分布。
英文摘要：
Ganymede's surface exhibits great geological diversity, with old dark terrains, expressed through the surface composition, which is known to be dominated by two constituents: H2O-ice and an unidentified darkening agent. In this paper, new investigations of the composition of Ganymede's surface at global scale are presented. The analyses are derived from the linear spectral modeling of a high spectral resolution dataset, acquired with the near-infrared ground-based integral field spectrometer SINFONI of the VLT. We find that the Oren-Nayar (1994) model, generalizing the Lambert's law for rough surfaces, produces excellent photometric corrections. Modeling confirms that Ganymede's surface composition is dominated by H2O-ice, mostly crystalline, as well as a darkening agent, but it also highlights the necessity of secondary species to better fit the measurements: sulfuric acid hydrate and salts. A latitudinal gradient and a hemispherical dichotomy are the strongest spatial patterns observed for the darkening agent, the H2O-ice, and the sulfuric acid: the darkening agent is the major compound at the equator and mid-latitudes, especially on the trailing hemisphere, while the H2O-ice and the sulfuric acid are mostly located at high latitudes and on the leading hemisphere. This anti-correlation is likely a consequence of the bombardment of the constituents in the Jovian magnetosphere which are more intense at higher latitudes. Furthermore, the modeling confirms that polar caps are enriched in small, fresh, H2O-ice grains while equatorial regions are composed of larger grains. Finally, the spatial distribution of the salts is neither related to the Jovian magnetospheric bombardment nor the craters. These species are mostly detected on bright grooved terrains surrounding darker areas. Endogenous processes, such as freezing of upwelling fluids in the ice shell, may explain this distribution.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
