Viktor Amazaspovich Ambartsumian (Վիկտոր Համբարձումյան in Armenian, Виктор Амазаспович Амбарцумян in Russian) (September 18, 1908 (Julian calendar: September 5) – August 12, 1996) was an Armenian-Russian astronomer and astrophysicist. One of the pioneers of theoretical astrophysics, he worked on the cosmogony of stars and galaxies, stellar dynamics, and gaseous nebulas. In 1947 he discovered stellar associations. He suggested that T Tauri stars are very young and that loose stellar associations are dissociating. September 18 is the 261st day of the year (262nd in leap years). ... 1908 is a leap year starting on Wednesday (link will take you to calendar). ... The Julian calendar was introduced by Julius Caesar in 46 BC, taking force in 45 BC or 709 ab urbe condita. ... September 5 is the 248th day of the year (249th in leap years). ... August 12 is the 224th day of the year (225th in leap years) in the Gregorian Calendar. ... 1996 is a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... An astronomer or spmething i cant inderstand is a scientist whose area of research is astronomy or astrophysics. ... Spiral Galaxy ESO 269-57 Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature and chemical composition) of astronomical objects such as stars, galaxies, and the interstellar medium, as well as their interactions. ... The Pleiades star cluster A star is any massive gaseous body in outer space. ... This article is about a celestial body. ... Stellar dynamics is the branch of astrophysics which describes in a statistical way the collective motions of stars subject to their mutual gravity. ... The Triangulum Emission Nebula NGC 604 lies in a spiral arm of Galaxy M33, 2. ... 1947 was a common year starting on Wednesday (link will take you to calendar). ... A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. ... T Tauri stars are a class of variable stars named after their prototype T Tauri. ...

Life

Viktor Amazaspovich Ambartsumian at a 100 AMD banknote

He was born in Tbilisi, Georgia. His surname is sometimes given as Ambarzumian or Ambarzumyan or Ambarzumjan, and his first name is sometimes given as Victor. His middle name is sometimes given as just Amazasp. Having graduated the Leningrad University he studied with Belopolsky in Pulkovo Observatory from 1928 to 1931. Viktor Amazaspovich Ambartsumyan at haryur dram (100 AMD) note, being in circulation between 1998 and 2004 when replaced by 100 AMD coins. ... Viktor Amazaspovich Ambartsumyan at haryur dram (100 AMD) note, being in circulation between 1998 and 2004 when replaced by 100 AMD coins. ... View of Tiflis from the Grounds of Saint David Church, ca. ... Categories: Russia-related stubs | Universities and colleges in Russia | Saint Petersburg ... Aristarkh Apollonovich Belopolsky (Аристарх Апполонович Белопольский) (July 13, 1854 (OS: July 1) – May 16, 1934) was a Russian astronomer. ... The Pulkovo Space Observatory (Пулковская астрономическая обсерватория in Russian), the principal space observatory of the Russian Academy of Sciences, located 19 km south of Saint Petersburg on Pulkovo Heights (75 m above the sea level). ... 1928 was a leap year starting on Sunday (link will take you to calendar). ... 1931 is a common year starting on Thursday. ...

He worked at the Pulkovo Observatory; the Byurakan Astrophysical Observatory, which he founded in 1946 and directed; Erevan University; and the Armenian Academy of Sciences, where he served as president from 1947 to 1993. He served as president of the International Astronomical Union during 1961–1964. He had four children: Ruben, Rafail, Karine, Egine. 1946 was a common year starting on Tuesday. ... 1947 was a common year starting on Wednesday (link will take you to calendar). ... 1993 is a common year starting on Friday of the Gregorian calendar and marked the Beginning of the International Decade to Combat Racism and Racial Discrimination (1993-2003). ... The International Astronomical Union (IAU) unites national astronomical societies from around the world. ... 1961 was a common year starting on Sunday (link will take you to calendar). ... 1964 was a leap year starting on Wednesday (link will take you to calendar). ...

Works

While at Pulkovo he also taught at the University of Leningrad and wrote the first Russian textbook on theoretical astrophysics. Most of his research was devoted to invariance principles applied to the theory of radiative transfer, inverse problems of astrophysics, and the empirical approach to the problems of the origin and evolution of stars and galaxies. In astronomy, stellar evolution is the sequence of changes that a star undergoes during its lifetime, the millions or billions of years during which it emits light and heat. ...

He was the first to suggest that T Tauri stars are very young and to propose that nearby stellar associations are expanding. He also showed that evolutionary processes such as mass loss are occurring in galaxies; worked on interstellar matter, radio galaxies, and active galactic nuclei; and was the principal organizer of two major conferences on SETI at the Byurakan Observatory in 1964 and 1972. T Tauri stars are a class of variable stars named after their prototype T Tauri. ... In astronomy, the interstellar medium (or ISM) is the matter and energy content that exists between the stars (or their immediate circumstellar environment) within a galaxy. ... An active galaxy is a galaxy where a significant fraction of the energy output is not emitted by the normal components of a galaxy: stars, dust and interstellar gas. ... The SETI Institute has received limited telescope time at the Arecibo Observatory in Puerto Rico. ... 1972 was a leap year that started on a Saturday. ...

Honors

Awards

• Bruce Medal (1960)
• Gold Medal of the Royal Astronomical Society (1960)
• Lomonosov Gold Medal (1971)

Named after him The Catherine Wolfe Bruce gold medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. ... 1960 was a leap year starting on Friday (link will take you to calendar). ... The Gold Medal is the highest award of the Royal Astronomical Society. ... The Lomonosov Gold Medal, named after Russian scientist and polymath Mikhail Lomonosov, is awarded each year since 1959 for outstanding achievements in the natural sciences and the humanities by the USSR Academy of Sciences and later the Russian Academy of Sciences (RAS). ... 1971 is a common year starting on Friday (click for link to calendar). ...

• Asteroid 1905 Ambartsumian

An asteroid is a small, solid object in our Solar System, orbiting the Sun. ...

External links

• Bruce Medal page
• Awarding of Bruce Medal
• Awarding of RAS gold medal

Obituaries

• BAAS 29 (1997) 1466
• JApA 18 (1997) 1
• JRASC 90 (1996) 351