Gerasimovich, Boris Petrovich

(b. Kremenchug, Russia, 19 March 1889; d. Moscow, U.S.S.R., October 1937)

astrophysics.

Gerasimovich’s father, a physician, was director of a district hospital. Geresomovich attended the Poltava Gymnasium but did not graduate, having been expelled for participation in the revolutionary movement. Only in 1909, after passing examination as an extern, did he receive his “certificate of maturity.” In 1910 he studied at the Faculty of Physics and Mathematics of Kharkov University, where his teachers in astronomy were the director of the astronomical observatory; Ludwig Struve, and the astrometrist N. N. Yevdokimov.

Gerasimovich received a prize in 1911 for his student composition” Aberratsia sveta"’ Aberration of Light”). After graduating from the university in 1914, be remained to prepare for an academic career. In 1916 he was a probationer at Pulkovo Observatory, studying astropgysics under A. A. Belopolsky and Sergei Kostinsky. Having passed his master’s degree examination” in 1917 Gerasimovich became a Privatdozent at Kharkov University. From 1920 to 1933 he was senior astronomer at the observatory, and from 1922 he was also professor of astronomy. At the same time Gerasimovich taught mathematics and mechanics at a number of higher educational institutions in Kharkov. In 1931 he was invited to head the astrophysics section of the Pulkovo Observatory, and in 1933 he was appointed director of the observatory.

In 1924 Gerasimovich made a scientific trip to England and France, and from 1926 to 1929 he was visiting professor at Harvard Observatroy, where both independently and in collaboration with Harlow Shapley, otto Struve, Willem Luyten, and Donald Menzel he conducted a number of scientific investigations. In 1926, 1932, and 1935 Gersimovich participated in the Copenhagen Congress of the German Astronomical Society, and in Cambridge, Massachusetts, and Paris sessions of the General Assembly of the International Astronomical Union.

Gerasimovich’s range of scientific interests was very Broad, and there are about 170 publications in his bibliography. Among them are works on photometrical and spectral research on variable stars (about eighty works), planetrary nebulas, emission stars, scientific works in the field of throretical astrophysics, stellar astronomy, the structure of the Galaxy, stellar statics, celestial mechanics, astrometry, solar physicsm and other problems. His research on semiregualr variable stars, which he conducted on materials from the rich collection of photographic plates of the Harvard Observatory, has retained’ its great value.

Gerasimovich was a pioneer in the study of planetary nebulas, which are expanded coulds thrown out at the time of the explosions of certain types of nonstationary stars. He studied the turbulent movement in gas nebulas and investigated the varied forms of the planetary nebuls as figures of equilibrium, which can accept masses of gas under the influence of the forces of gravity of the central star and the forces of light repulsion (light pressure). Gerasimovich also studied the processes of ionization of planetary nebulas, determined the luminosity of their nuclei (the central stars), and came to the important conclusion that the masses of their central stars are small. This hypothesis was confirmed by the later research of others.

Gerasimovich was one of the first to emphasize the important role of computation of interstellar light absotption. (which weakens the visible brightness of stars and causes their teddening in the study of the structure of the Galaxy. In particular he used an original method of studying the apparent change of the mean distance of variable stars of the Cephied type from the galactic plane as a function of their distance from the sun for an estimate of the value of the interstellar absorption of light.

Gerasimovich was responsible for an important investigation of the dynamics of the stellar system as the site of the simultaneous action of regular and Milky Way and its insufficient brilliance in the direction of the constellation Sagittarius (where the dynamic center of the Galaxy is found) again led him to the belief in the essential role of the interstellar substratum, which forms a substantial condensation in space and at the same time causes a weakening of the brightness of the Milky Way.

With the American astronomer W. Luyten, Gerasimovivh determined in 1927 the altitude of the sun over the base plane of the Galaxy as thirty-four parsecs (contemporary determinations give fifteentwenty).

The study of the sun and the organization of and participation in expeditions to observe total solar eclipses occupied a special place in Gerasimovivh’s scientific work. In the later years of his life, in addtion to the other responsibilities, he was president of the Commission for the Study of the Sun of the Astronomical Council of the Soviet Academy of Sciences and president of Sciences for the preparation of all expeditions to observe the toal eclipse of 19 June 1936. This was the first eclipse of the sun for which, on Gerasimovich’s initative, the whole program’s photographic observations were organized in a unified way, using six uniform, standard coronagraphs placed along the zone of visibility of the total phase of the eclipse. As a result, very valuable data on the movement of matter in the solar corona were obtained.

Gerasimovich’s monograph Solnechnaya fizika (“Solar Physics,” in Ukrainian, 1933; end ed., in Russian, 1935) is an excellent description of the physics of the sun, summing up the achievements of Sovier monographs, Vselennaya pri svete teorii otnositelnosti (“The Universe in Light of the Theory of Relativity,” 1925), was of great importance in popularizing the theory of relativity and Einstein’s cosmological ideas. An outstanding role in the preparation of Soviet astronomers of the following generations was played by Kurs astrofiziki i zvezdnoy astronomii (“Course in Astrophysics and Stellar Astronomy”), which contained, among other works, a number of his original articles and was published under his direction in 1934 and 1936.

Gerasimovich’s scientific activity was recognized by awards in the Soviet Union (1924, 1926, 1936), the United States (1928), and France (1934). He was elected a member of the All-Union Astronomical Geodesical Society, the American and German astronomical societies, the Royal Astronomical Society, the American Association of Observers of Variable Starts, and the International Astronomical Union.

BIBLIOGRAPHY

I. Original Works. Gerasimovich’s writings include Vselennaya pri svete teorii otnositelnosti (“The Universe in Light of the Theory of Relativity”; Kharkov, 1925); “On the Radiative and Mechanical Equilibrium of Spherical Planetary Nebulae.” in Astronomische Nachrichten, 225 (1925), 89; “Ionization in Nebular Matter.” in Harvard Reprints. Harvard College Observatory, 38 (1927); “On the Distance of the Sun From the Galactic Plane,” in Proceedings of the National Academy of Sciences of the United States of America, 13 (1927), 387-390, written with Willem Luyten; “On the Luminosities of the Nuclei of Planetary Nebulae,” in Publications of the Astronomical Society of the Pacific, 39 (1927), 19; and “On the Spectroscopic Absolute Magnitude Effect,” in Circular, Astronomical Observatory of Harvard College,311 (1927), 1-11.

For the works on semiregular variable stars, see “V Vulpeculae,” ibid., 321 (1927), 1-11; “The Photographic Light Curves of R. Scuti,” ibid., 323 (1928), 1-3; “Secular Changes in the Mean Period of R Scuti (1795-1927),” ibid., 333 (1928), 1-5; “V Ursae Minors and SW Persei,” written with L. Hufnagel: “A General Study of RV Tauri Variables,” ibid., 341 (1929), 1-15; and “On Variables of the Intermediate Group,” ibid., 342 (1929), 1-9.

See also “Spectrophotometric Temperature of Early Stars,” ibid., 339 (1929), 1-27; “On the Photographic Absolute Magnitudes of the Nuclei of Planetary Nebulae,” in Bulletin, Harvard College Observatory, 864 (1929), 9-14; “The Nuclei of Planetary Nebulae,” in Observatory, 54 (1931), 108; “Probability Problems Connected With the Discovery of Variable Stars in a Photographic Way,” in Doklady Akademii nauk SSSR, 4 , nos, 5-6 (1931), 43-45; “Rayleighsche Streung und anomale Sterntemperaturen,” in Zeitschrift für Astrophysik, 4 (1932), 265-281; “Nonstatistic Hydrogen Chromospheres and the Problem of B Stars,” 94 Monthly Notices of the Royal Astronomical Society, 94 (1933), 737-765; Kurs astrofiziki i zvezdnoy astronomii (“Course in Astrophysics and Stellar Astronomy”), II (Moscow-Leningrad, 1936), chs. 3, 6-12; “The Zero Point of the Cepheids’ Period-Luminosity Relation,” in Observatory, 57 (1934) 22-23; “B Spectrum Variables,” ibid., 58 (1935), 115-124; Solnechnaya fizika (“Solar Physics”; 2nd ed., Kharkov, 1935); “Cosmic Absorption and the Galactic Concentration of Classical Cepheids,” in Tsirkular Glavnoi astronomichseskoi observatorii v Pulkove, no. 10 (1936), 9-11; “On the Behavior of Absorption Lines in the Spectrum of P Cygni,” ibid., no. 17 (1936), 13-15; “The System of Polaris.” ibid., no. 19 (1936), 739; “A Unitary Model of the Galactic System,” in Nature, 137 (1936), 739; and “On the Illumination of a Planet Covered With a Thick Atmosphere,’ in Izvestiya Glavnoi astronomicheskoi observatorii v Pulkove, no. 127 (1937), 1-32.

II. Secondary Literature. On Gerasimovich or his work, see Astronomia v SSSR za 40 let 1917-1957 (“Astronomy in the U.S.S.R. for Forty Years”; Moscow, 1960), pp.54, 120, 287, 294, 332; Razvite astronomii v SSSR (“The Development of Astronomy in the U.S.S.R.”; Moscow, 1967), pp. 206, 215-217, 219; Y. G. Perel, “B. P. Gerasimovich,” in Astronomichesky kalendar na 1964 g. (“Astronomical Calendar for 1964”; Moscow, 1936), pp. 256-258; and O. Struve. “About a Russian Astronomer,” in Sky and Telescope, 16 , no. 8 (1957), 379-381.

P. G. Kulikovsky