发表机构
University of Arizona; University of Washington; University of Idaho; Johns Hopkins Applied Physics Laboratory（亚利桑那大学; 华盛顿大学; 爱达荷大学; 约翰斯·霍普金斯大学应用物理实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用克莱门汀月球轨道器对地球的3744次观测，生成5个波段的整盘光度相位曲线，发现颜色变化最佳拟合含海洋镜面反射的模型，并解释无镜面反射时颜色仍符合预测的现象，强调高相位角观测对类地系外行星表征的重要性。
AI 中文摘要
行星天体的相位曲线可以揭示其大气和表面的关键细节，包括表面液态海洋的存在。地球的相位曲线可以为寻找类地系外行星上的宜居表面环境提供信息，但此类相位曲线相当罕见。克莱门汀月球轨道器在1994年2月至5月期间对地球进行了3,744次观测。这些观测覆盖了3.4度至139.1度的相位角范围。根据这些数据，我们生成了地球在5个不同波段（波长范围400纳米至1000纳米）的相位曲线。我们对相位曲线进行外推拟合，以推导地球在每个滤光片下的几何反照率。我们检查了地球颜色随相位角的变化，发现观测值最佳拟合于包含海洋镜面反射贡献的模型。我们还发现了一些观测，其中镜面反射的贡献极小，但盘积分颜色与镜面反射模型的预测一致；我们提出这可以通过盘上存在光学云来解释。这些发现强调了高相位角地球观测对于高保真地球模型以及未来通过直接成像表征类地系外行星工作的重要性。
英文摘要
The phase curve on a planetary object can reveal key details about its atmosphere and surface, including the presence of surface liquid oceans. Phase curves for Earth can inform the search for habitable surface environments on terrestrial exoplanets, but such phase curves are quite rare. The Clementine lunar orbiter made 3,744 observations of the Earth between February and May of 1994. These observations spanned phase angles between 3.4 and 139.1 degrees. From these data, we produce phase curves of Earth in 5 distinct bands with wavelengths between 400 nm and 1000 nm. We extrapolate fits to the phase curves to derive the geometric albedo of Earth in each filter. We examine the Earth's color as a function of phase angle and find the observed values are best fitted by models that include contributions from ocean glint. We also find a number of observations where contributions from glint are minimal but the disk-integrated color is in line with the glinting model predictions; we propose that this can be explained by the presence of optically clouds on the disk. These findings stress the importance of high-phase Earth observations for high-fidelity Earth models and for future efforts to characterize terrestrial exoplanets via direct imaging.
Comments16 pages, 10 figures
