an exhaustive analysis of the photogravitational interaction between stars and gas clouds. The results obtained provide a possible explanation for the phenomenon of the stellar velocity increase with age. Other scientific achievements T. A. Agekian has initiated a numerical study of triple systems and a statistical analysis of results. Among other results, T. A. Agekian and his collaborators found the probabilities of capture and exchange. A classification of the states of triple systems was proposed. T. A. Agekian also studied the problem of motion in the field of an axially symmetrical potential, and being an author of new methods, achieved some new results in this difficult topic. Professor T. A. Agekian is one of the pioneers of Stellar Dynamics. Since the 1970s, T. A. Agekian studied mainly the problem of motion in the field of an axially symmetrical potential. He proposed new methods and achieved some new results in the topic. References 1913 births 2006 deaths People from Batumi People from Batum Oblast Soviet astronomers Astronomers from Georgia (country) Armenian astronomers Saint Petersburg State University alumni Academic staff of Saint Petersburg State University Soviet military personnel of World War II Georgian people of Armenian descent Soviet Armenians