Atmospheric and Surface Composition of Titan from Specular Reflections

这个项目是为了限制土星卫星泰坦的表面和大气成分。土卫六表面的光谱观测，无论是从原位航天器还是地球上的望远镜，都因土卫六厚厚的大气层而变得复杂，光线必须穿过大气层，而大气层的组成和结构却知之甚少。该项目的关键内容是用卡西尼号航天器上的视觉和红外绘图分光计观测太阳从土卫六的一个碳氢化合物湖的掠射角镜面反射。主要研究者（PI）打算利用镜面反射的波长独立性来隔离大气对总光谱的贡献。拟议的工作包括三个具体任务：（1）使用镜面反射获得的透射光谱探索土卫六极地大气的组成;（2）使用VIMS光谱在5微米透射窗口中校正大气影响，限制可能的表面有机物质的组成;（3）使用校正的光谱绘制表面水冰暴露的程度。该项目将支持一个研究生和一个本科生在一个以前不活跃于天文学研究的机构的工作，为扩大爱达荷州居民对科学的参与提供机会。该项目由天文科学部和刺激竞争性研究实验计划办公室（EPSCoR）共同资助。

This project is an effort to constrain the surface and atmospheric composition of Saturn's moon Titan. Spectroscopic observations of the surface, whether from in situ spacecraft or Earth-based telescopes, are complicated by Titan's thick atmosphere, through which the light must traverse, and the composition and structure of which are poorly known. The key element of this project is the observation of a grazing-angle specular reflection of the Sun from one of Titan's hydrocarbon lakes by the Visual and Infrared Mapping Spectrometer (VIMS) on the Cassini spacecraft. The Principal Investigator (PI) intends to exploit the wavelength independence of the specular reflection to isolate the atmospheric contributions to the total spectrum. The proposed work consists of three specific tasks: (1) to explore the composition of Titan's polar atmosphere using the transmission spectrum obtained from the specular reflection; (2) to constrain the composition of possible surface organic species using VIMS spectra in the 5-micron transmission window corrected for atmospheric effects, and (3) to map the extent of surface water ice exposures using the corrected spectra. The project would support the work of a graduate student and an undergraduate student at an institution that has not previously been active in astronomy research, providing an opportunity to broaden participation in science among residents of Idaho. This project is jointly funded by the Division of Astronomical Sciences and the Office of the Experimental Program to Stimulate Competitive Research (EPSCoR).