Charged environment on Phobos surface

There are various astronomical objects in our solar system, but their origins are not yet fully understood. One of the most interesting projects to solve such mysteries of stellar evolution is the exploration of asteroids, as represented by Hayabusa mission. On the surface of asteroids, the materials in the early stages of the solar system formation exist, but at the same time, solar wind and cosmic ray irradiation on the surfaces of celestial objects without atmospheres are causing changes in surface materials (space weathering). Therefore, in order to find out the origin of materials from surface materials, it is necessary to know the environment in which the objects are located. We focus on the phenomenon that the surface of a small object is charged when it is exposed to the solar wind, and we study the effect of space weathering on the surface. This study will be useful for the analysis of surface materials brought back by the sample return in the MMX mission, which is the next Japanese mission after Hayabusa2.　

(Master’s course 2nd, Masaki Tanabe)