1955 RD1. Discovered 1955 Sept. 14 at the Goethe Link Observatory at Brooklyn, Indiana.

Named in honor of Yusuke Hagihara {1897–1979}, professor of astronomy at the University of Tokyo from 1935 to 1957, Director of the Tokyo Observatory from 1946 to 1957, and long an inspiring leader and teacher, principally in celestial mechanics and also in several other branches of astronomy and astrophysics. Best known for his theory of libratory motions and general discussion of stability problems in celestial mechanics, he has also made important contributions to the study of the velocity distribution of free electrons in planetary nebulae. In recent years he has produced a monumental five-volume treatise on celestial mechanics. He served as a vice-president of the IAU during 1961–1967 and as president of Commission 7 during 1964–1967. (M 4419)

This minor planet was named at the IAU Symposium No. 81, The Dynamics of the Solar System, held in Tokyo in May 1978 on the occasion of his 81st birthday.

Obituaries published in Phys. Today, Vol. 32, No. 6, p. 71 (1979); Q.J.R. Astron. Soc., Vol. 20, p. 325–328 (1979).