AI 中文总结
研究火卫一表面形态及光谱异质性成因，核心方法是用RAVEL代码结合动力学模型计算风化层轨迹，主要贡献是揭示风化层迁移路径，提供3D形态动力学图谱，有助于确定火星卫星探测航天器样本地理来源。
AI 中文摘要
火卫一在高度动态的环境中演化，表面物质运动受自身引力、随时间变化的火星潮汐和惯性力共同影响。在这种低重力状态下，仅从地形坡度无法推断松散物质位移，因此动力学方法对解释火卫一表面形态及支持日本宇宙航空研究开发机构领导的火星卫星探测任务至关重要。我们使用RAVEL代码，在火卫一数字地形模型上应用结合表面加速度场和摩擦力的动力学模型计算表面风化层轨迹。该模型不预测边坡失稳触发，而是研究运动开始后物质优先移动方向，揭示了大规模连贯动力学区域和风化层迁移路径网络。风化层迁移路径最终位置与光滑、低起伏地形及光谱中性单元相关，对应长期风化层填充形成的沉积地幔；粗糙、高地势且有大量小陨石坑和蓝色光谱斜率的区域往往是动态活跃或剥蚀源区；光谱红色地形通常与动态平静、形态粗糙表面相关，模型预测风化层运动可忽略不计，表明是较老、较少重新加工的单元。这些模式表明火卫一的许多表面形态和光谱异质性可由表面加速度场沿风化层迁移路径驱动的长期风化层重新分布来解释。我们提供了火卫一表面风化层迁移路径的3D形态动力学图谱，这将有助于确定火星卫星探测航天器采集样本的地理来源。
英文摘要
Phobos evolves in a highly dynamical environment where surface-material motion is controlled by the combined effects of self-gravity, time-dependent Martian tides, and inertial forces. In such a low-gravity regime, the displacement of loose material, cannot be inferred from topographic slope alone, making a dynamical approach essential for interpreting Phobos' surface morphology and for supporting the Martian Moons eXploration (MMX) mission led by JAXA. Here, using our RAVEL code, we apply a dynamical model that combines the surface acceleration field with friction on a digital terrain model of Phobos to compute surface regolith trajectories. The model does not aim to predict the triggering of slope failure. Instead, it addresses where material would preferentially move once motion is initiated. This reveals large scale coherent dynamical regions and a sparse network of preferred regolith transport routes, termed here Regolith Migration Pathways (RMPs). The final positions of the RMPs correlate with smooth, low-relief terrains and spectrally neutral units, consistent with depositional mantles formed by long-term regolith infill, whereas rough, high-standing areas with abundant small craters and blue spectral slopes tend to correspond to dynamically active or denuded source regions. In contrast, spectrally red terrains are generally associated with dynamically quiet, morphologically rough surfaces where our model predicts negligible regolith motion, suggesting older, less frequently reworked units. Taken together, these patterns indicate that much of Phobos' surface morphology and spectral heterogeneity can be explained by long-term regolith redistribution driven by the surface acceleration field along RMPs. We provide a 3D morphodynamic atlas of RMPs across Phobos' surface, which will be useful for constraining the geographical provenance of samples to be collected by the MMX spacecraft.
Comments46 pages; 21 figures; 29 references; 4 appendices
