Studies on production processes of exospheric atmospheres of Mercury and Io based on development of a spectro-imager

1.大气层二维光谱成像系统的研制开发了一种用于探测行星和卫星大气层外钠发射的光谱成像系统。该系统包括1)由光纤束制成的尺寸转换光学元件和2)将尺寸转换光学元件连接到出光和入射光学元件的F数调节光学元件。光纤束布置在12x12(入口)和144x1(出口)。该系统安装在光学台上，与东北大学直径60 cm的库德望远镜(入口侧)和高分辨率光栅谱仪(出射侧)相连。将光谱数据投影到Li-N_2制冷的CCD相机上，并在计算机上重建成光谱图像。利用光谱成像系统对伽利略卫星之一的木卫一和水星的外层大气进行了观测。有人建议，Product…木卫一大气层的更大速率取决于木卫一的相角(木卫一相对于木星的表观位置)。为了证实这种依赖关系，我们对不同的Io相角进行了观测，得到了有意义的数据集。另一方面，在水星基本上远离太阳的时候，人们对水星进行了密集的观测。由于主要是恶劣的天气条件，在研究期内还没有获得足够可靠的图像来研究采气过程。我们计划在2006年6月之后进行后续观测，届时水星将在2006.3除了太阳之外被观测到最多。研究采气过程的数值模拟发展了蒙特卡罗模拟模型，并将其应用于采气过程的研究。作为水星大气的结果，研究表明，太阳风质子的离子溅射在水星表面产生大气的效率比之前预测的要高得多。对于木卫一的大气，推测其大气量可能受木星磁层等离子体的溅射和凝视与太阳光的光子激发脱附的耦合过程控制。较少

1. Development of a 2D spectro-imaging system for exospheric atmospheresA spectro-imaging system for detection of sodium emissions of exospheric atmospheres of planets and satellites is developed. The system consists of 1)a dimension converting optics made of an optical fiber bundle, and 2)a F-number adjusting optics to connect the dimension converting optics to light-entrance and exit optics. The optical fiber bundle is arranged in 12x12(entrance) and 144x1(exit). The system is set up on an optical bench and connected to the 60cm diameter coude telescope (entrance side) and high-resolution grating spectrometer (exit side) of Tohoku University. A spectrum datum is projected onto a Li-N2 cooled CCD camera and reconstructed to a spectro-image on a computer.2. Observations of exospheric atmospheres of Io and MercuryObservations of exospheric atmospheres of Io, one of the Galilean satellites, and Mercury have been made using the spectro-imaging system. It has been suggested that production … More rate of Io's atmosphere depends on Io's phase angel (Io's apparent position with respect to Jupiter). In order to confirm the dependence, we have made observations of Io for various Io's phase angles and obtained significant data-sets. On the other hand, Mercury observations have been made intensively for the period when Mercury is viewed largely apart from the sun. Due to bad weather condition in main, reliable images for investigating gas production processes have not been sufficiently acquired in the research period. We plan to make follow-up observations after June, 2006 when Mercury is viewed most largely apart from the sun in 2006.3. Numerical simulation for investigating gas production processesA Monte-Carlo simulation model has been developed and adopted for the investigations of gas production processes. As the result for Mercury's atmosphere, it is suggested that ion sputtering by solar wind protons is operated further more effectively than previously predicted on Mercury's surface to product the atmosphere. As for Io's atmosphere, it is inferred that the amount of the atmosphere might be controlled by the coupling process of sputtering and/or peering by Jupiter's magnetospheric plasma and the photon stimulated desorption by the sunlight. Less