AI 中文总结
本研究计算火卫一三个光谱单元的红外-可见光反照率比值，与MP3C中小行星数据对比，发现其值覆盖原始小行星范围，支持火卫一可能起源于小行星的结论。
AI 中文摘要
目的：红外与可见光反照率的比值pIR/pV是小行星表面在可见光至近红外波长范围内光谱斜率的简单替代指标，本研究旨在评估火卫一的三个光谱单元是否与原始小行星群体占据相同的光谱参数空间，以确认其可能的小行星起源。方法：针对火卫一的三个光谱单元（红色、过渡型和蓝色），通过对比火星快车号OMEGA仪器获取的可见光（0.50-0.60μm）和近红外（3.1-3.8μm）范围内的归一化反射率，提取平均归一化反射光谱，计算红外-可见光反照率比值的替代指标RP；再利用小行星物理性质目录（MP3C）汇编的可见光和红外反照率数据库，计算小行星的pIR/pV值（RA），并与火卫一的结果进行比较。结果：红色、过渡型和蓝色区域的RP分别在2.90-3.12、2.32-2.35、1.64-1.85之间，这些值覆盖了原始小行星群体所在的范围，其中过渡型和红色区域与pIR/pV域内的高比值 regime 重合，该 regime 通常与红斜率原始小行星相关，包括D型、T型天体以及木星特洛伊小行星。
英文摘要
Aims. The ratio between infrared and visible albedo, pIR/pV, provides a simple proxy for the spectral slope of asteroid surfaces between the visible and near-infrared wavelength ranges. The aim of this work is to assess whether the different spectral units of Phobos occupy the same spectral parameter space as the primitive asteroid populations in order to confirm or not its possible asteroidal origin. Methods. For each of the three spectral units of Phobos (Red, Transitional and Blue), we extracted averaged, normalised reflectance spectra by comparing normalised reflectance in the visible (0.50-0.60 $μ$m) and near-infrared (3.1-3.8 $μ$m) wavelength ranges from the Mars Express OMEGA instrument, to compute a proxy for the infrared-visible albedo ratio ($R_P$). Then, using the database of visible and infrared albedos compiled in the Minor Planet Physical Properties Catalogue (MP3C), we computed asteroid pIR/pV values ($R_A$), to compare to those for Phobos. Results. The $R_P$ for the Red, Transitional and Blue regions vary between 2.90 and 3.12, 2.32 and 2.35, 1.64 and 1.85 respectively. These values span a range occupied by primitive asteroid populations, with the Transitional and Red regions coinciding with the high ratio regime within the pIR/pV domain, which is commonly associated with red-sloped primitive asteroids, including D- and T-type objects as well as Jupiter Trojans.
Comments9 pages, 3 figures, 1 table, accepted for A&A
