Japanese asteroid studies in the century after the discovery of the Hirayama families

摘要

A number of studies relating to asteroids have been conducted by Japanese astronomers in the century since the discovery of asteroid families by Kiyotsugu Hirayama in 1918. The true concept of the "asteroid family" was recognized correctly by a few eminent astronomers like Brouwer (1950) in the astronomical community worldwide by the 1970s. The Hirayama's monumental discovery likely stimulated research activities on the dynamics of asteroids after WWII in Japan, as represented by the Kozai mechanism (Kozai (1962)).