Abstract:
The observations with the ground- and space-based telescopes and especially in several space missions in recent over 30 years have enormously improved our understanding of small bodies in the solar system. It is already known that the complex and diverse topographical features of the surface of those small bodies are closely related to their geological evolution, and therefore, they have provided important information of the early solar system. This paper first gives a brief introduction of the rationales and the methods of how to determine the shape and the topography of small bodies based on the astronomical observations. Then, based on the retrieved data from the related launched spacecrafts, the surface environments and the physical characteristics of asteroid 433 Eros, 25143 Itokawa, 4179 Toutatis, 162173 Ryugu, 101955 Bennu and 486958 2014 MU69 are discussed, focusing on their bulk shapes, the configurations and the distributions of the boulders, the appearance and distributions of the craters, the slope angles, the linear features like the grooves and the ridges, and the mass loss evidence of the surface regolith, as well as their relationships with the formation history of each asteroid. Finally, we present several mechanisms that may affect the topography of asteroids, to provide some guidance for the scientific research of target asteroids concerning the next Chinese missions.