Alexandr Boyarchuk (June 21, 1931 – August 10, 2015) was a

Russian Russian(s) may refer to: *Russians (), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *A citizen of Russia *Russian language, the most widely spoken of the Slavic languages *''The Russians'', a b ...

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

and

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

Life

In 1953, he graduated from

Leningrad University Saint Petersburg State University (SPBGU; ) is a public university, public research university in Saint Petersburg, Russia, and one of the oldest and most prestigious universities in Russia. Founded in 1724 by a decree of Peter the Great, the uni ...

. After graduation, he worked at the Crimean Astrophysical Observatory, which was under direction of the USSR Academy of Sciences at the time. Later, he was elected a corresponding member of the same organization, and worked as an academician there until 1987. From 1987 to 2003, he was the director of the Institute of Astronomy of the Russian Academy of Sciences. From 1991 to 1993, he was also President of the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

Scientific achievements

Boyarchuk specialized in studying the physics of stars. He carried out numerous studies regarding the chemical composition of stars of various classes, in particular, he discovered an excess of helium in

Beta Lyrae Beta Lyrae (β Lyrae, abbreviated Beta Lyr, β Lyr) officially named Sheliak (Arabic: الشلياق, Romanization: ash-Shiliyāq) ( IPA: ), the traditional name of the system, is a multiple star system in the constellation of Lyra. Base ...

. Boyarchuk also studied the motion of stellar atmospheres, as well as the rotation of stars. He devoted a number of his works to non-stationary stars. He was the developer of a model of symbiotic stars. Based on this model, he obtained estimates of the mass, size, temperature and other characteristics of these objects. Together with E.R. Mustel, he proposed a model for the envelope of new stars. Under the leadership of Boyarchuk, the ultraviolet telescope

Astron ASTRON is the Netherlands Institute for Radio Astronomy. Its main office is in Dwingeloo in the Dwingelderveld National Park in the province of Drenthe. ASTRON is part of the institutes organization of the Dutch Research Council (NWO). History A ...

was created.

Death

Boyarchuk died on August 10, 2015, at the age of 84 in

Moscow Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents with ...

References

1931 births 2015 deaths Russian physicists Russian astronomers People from Grozny Soviet astrophysicists Presidents of the International Astronomical Union {{europe-astronomer-stub