(Proposal ID) S13A-113 (PI) Usui, Fumihiko (Proposal Title) Exploring Water on Planetesimal Remnants Using AKARI Asteroid Catalog (Abstract) We propose a program to search water ice and aqueously altered silicates on surface of carbonaceous asteroids in the outer main belt regions which have high albedo measured with the infrared astronomical satellite AKARI. The distribution of water provides important information to understanding of the formation and evolution of the solar system. One of the candidates of water reservoir in the outer main belt region is B-type asteroid, which is thought to be primitive and volatile-rich. Although several spectroscopic surveys for B-types were executed, there is no report about detection of water ice on B-types at present. The previous targets are biased for lower albedo objects, because of lack of albedo information. Recent albedo data brought by AKARI opens the new possibility of detecting water ice on asteroids. We plan to observe high-albedo B- and C-type asteroids which are considered as the candidates of planetesimal remnants with water ice beyond 3 AU. Thanks to a large aperture of Subaru Telescope and a high altitude of Mauna Kea, it can be only possible to detect a weak signal of water. From these data, we aim to make a comprehensive analysis for classification of primitive asteroids and revealing the nature of these components.