POWRE: Probing Titan's Surface With Acousto-Optic Imaging

土卫六是土星最大的卫星。土卫六的表面将使用高空间和光谱分辨率成像的强大组合，在迄今为止未从地球上探索过的波长区域进行探索。土卫六大气中的甲烷吸收导致大气“窗口”在~ 0.83和2微米波长之间，甲烷分子的吸收很低，允许探测土卫六表面。先前对土卫六表面的空间分辨率成像显示，它的亮区和暗区是分开的，这意味着土卫六并没有像之前认为的那样被一个全球性的碳氢化合物海洋所覆盖。声光可调滤光相机具有比窄带滤光片更高的光谱分辨率，并且能够调谐到0.5 - 1.05微米之间的任何波长，用于在0.94微米的大气窗口中观测土卫六的图像。这些观测是在1999年秋天由威尔逊山天文台的100英寸望远镜完成的，该望远镜配备了自适应光学系统，可以对土卫六的圆盘进行高空间分辨率的成像。1999年秋季的观测覆盖了土卫六的一个半球，第二组观测计划在2000年秋季进行，将覆盖相反的半球。因此，绘制泰坦表面的完整地图将成为可能。这两个数据集将以相同的方式进行简化和建模，以获得土卫六表面在0.9微米波长窗口内的反射率信息。当与其他研究人员在波长更长的区域近红外大气窗口中观察的结果进行比较时，土卫六明亮和黑暗区域的光谱依赖性将被揭示出来。这将为土卫六表面的组成提供新的见解，这将是一个及时的结果，预计卡西尼/惠更斯卫星将于2004年探测土卫六。研究生和本科生参与所有层次的研究，将加强新墨西哥大学这所少数民族大学的科学教育。本项目由数学和物理科学理事会天文科学司和多学科活动办公室资助

AST -0074923ChanoverTitan is the largest moon of the planet Saturn. Titan's surface will be explored using a. powerful combination of high spatial and spectral resolution imaging in wavelength region heretofore unexplored from the Earth. The methane absorption in Titan's atmosphere results in atmospheric "windows" between ~ 0.83 and 2 microns wavelength where the absorption of the methane molecule is low, allowing the surface of Titan to be probed. Previous spatially resolved imaging of Titan's surface revealed discrete bright and dark regions, which imply that Titan is not covered with a global hydrocarbon ocean as had been previously suggested. An acousto-optic tunable filter camera, which has higher spec-tral resolution than narrow-band filters and the ability to tune to any wavelength between 0.5 - 1.05 microns, was used to make observations of the image of Titan in the 0.94 micron atmospheric window. These observations were made in the fall of 1999 from the Mount Wilson Observatory 100-inch telescope, which is equipped with an adaptive optics system that allowed for high spatial resolution imaging of Titan's disk. The fall 1999 observations covered one hemisphere of Titan, and a second set 0f observations is planned for the Fall of 2000 that will cover the opposite hemisphere. Thus a complete mapping of Titan's surface will be possible. Both data sets will be reduced and modeled in the same manner to yield information about the reflectivity, of' Titan's surface in the 0.9 micron wavelength window. When compared with results of other investigators looking in longer wavelength regions near-infrared atmospheric windows, the spectral dependence of Titan's bright and dark regions will be revealed. This will provide new insight into the composition of Titan's surface, which will be a. timely result in anticipation of the Cassini/Huygens satellite probe mission to Titan in 2004. The participation of a graduate and undergraduate student in all levels of the research will enhance science education at New Mexico Stale University, a minority univer-sity. This project is funded by the Division of Astronomical Sciences and the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate.***