Tadevos AGHEKIAN (1913-2006)

 

Tadevos Artem Aghekian is one of the Soviet Armenian merited astronomers. In the result of his productive activity numerous significant scientific results, as well as a number of distinguished scientists and classical monographs of astronomy were created.

 

Tadevos Aghekian was born on May 12, 1913 in Batumi. In 1938 he graduated from the mathematical-mechanical department of the Leningrad State University. In 1938-1941 he worked at a secondary school and parallelly studied at the correspondence post-graduate course of Leningrad State University. In 1941-1945 Aghekian participated in the Great Patriotic War in the post of chief of the staff of anti-aircraft artillery regiment (with title of a captain). For his military services he was awarded a Second-rank Order of the Great Patriotic War and medals. After the demobilization he returned to Leningrad State University and since 1946 he professed stellar dynamics, stellar kinematics and stellar statistics. In 1947 he defended his candidate thesis and in 1958 he became a doctor of physical-mathematical sciences. In 1961 he was honored with a professorship. His scientific researches refer to the problems of galactic astronomy, dynamics of stellar systems, stellar statistics and celestial mechanics. He obtained the main scientific results in the spheres of the theory of irregular field of stellar systems, dynamics of stellar systems based on data of radio observations, theory of motion in the field of rotational-symmetrical potential.

 

Aghekian investigated in detail the role of diffuse matter in the problems of stellar dynamics. Taking into consideration the gravitational and radiation pressure forces he obtained a mathematical expression for the star acceleration in the interaction of the star with the system of dusty clouds. He has displayed that while passing from early subclasses to later ones the phenomenon of growth of residual velocities of stars of O and B spectral classes is explained by the acceleration obtained as a result of interaction of hot giants with diffuse matter. He discussed the joint influence of galactic clustering and slice-shaped structure of absorbing matter on the visible distribution of galaxies. Aghekian worked out a method of investigating the kinematics of the Galaxy with the profile of 21cm wavelength radio line profile of neutral hydrogen. He investigated the evolution of rotational quasi-stable systems of interacting bodies. He proposed a method of investigation of characteristics of motion in the field of potential given with help of gradients of the field of directions. He adjusted the concept of complanarity of numerous stellar systems and he made a number of conclusions concerning the shift complanarity during the evolution. He observed a few general regularities of evolution of rotational systems of interacting bodies.

 

In common with scientific researches Aghekian paid great attention to pedagogical work and to the popularization of science. He is the author of textbooks devoted to the problems of use of the theory of probability and mathematical statistics (“The principles of theory of errors for astronomers and physicists”, “The theory of probability for astronomers and physicists”), a number of chapters of “Course of astrophysics and stellar astronomy” (1951) and the monograph “Stars, galaxies, Metagalaxy” (3 editions, the last one in 1981). The latter was also translated and published in English, Italian and Romanian. Ten candidate theses were defended under Aghekian’s supervision, and the four of his pupils defended a doctorate thesis as well.

 

Tadevos Aghekian passed away on January 15, 2006 in Leningrad. For his great contribution in the development of astronomy the small planet of Solar System N 3862 was named after Aghekian.