Zadig MOURADIAN (1930-2020)


The well-known astrophysicist Zadig Mouradian was one of the prominent French scientists of Armenian origin and was widely known among world theoretical astronomers and specialists in Solar physics.


Zadig Mouradian was born on July 10, 1930 in Bucharest (Romania). He graduated from the faculty of Physics and Mathematics of the University of Bucharest in 1954. During 1957-1980 he was a researcher in Bucharest astronomical institute. In October 1958 he moved from Bucharest to France. Since 1959 he was a researcher of the Department of Solar Physics in Meudon campus of Paris Observatory (Observatoire de Paris-Meudon). In 1965 he passed PhD defense and earned his doctorate degree in Physical sciences in Sorbonne University (Paris).


The scope of Mouradian works include Solar physics, more specifically ejection of Solar matter from Chromosphere (Solar wind); disappearance of prominence with the increase of the temperature; fields of solid body rotation causing magnetic streams. “Mouradian effect” discovered by him allows to reveal phenomena of the outer layer of the Sun through radial velocity.


Among Mouradian’s important scientific results it is worth mentioning the first observation of magnetic field evolution of Solar active region before, during, and after the Solar flare; the discovery of the main reason of Solar wind by the transfer of matter from Solar chromosphere to corona through Solar spicules; the measurement of limb darkening; “Mouradian effect” of optically thick spectral lines (velocities of Solar atmosphere create Doppler shifts, which decrease optical thickness in the center of the lines); the discovery of thermal disappearance of prominence caused by heating; designing and supervising the construction of 8m Solar spectrograph for Pic du Midi Observatory (Pyrenees, France), which functions till today; the development and supervision of digital detection, analysis, sketching and computer program principle of “Synoptic maps of Solar activity” (the world's only synoptic maps with computer control); the suggestion of a new method of the Solar rotation velocity that discovers new parameters of Solar activity.


In total, Mouradian is author and co-author of 160 scientific papers. It is interesting to note that he witnessed 7 total Solar eclipses, during which conducted observations. In the field of Solar Physics, he established international collaborations with scientists from various countries, namely Armenia, Bulgaria, China, Japan, Romania, Russia and USA. He also lectured at the faculty of Physics and Mathematics of the University of Bucharest teaching Solar Physics. He supervised a number of PhD theses.


Mouradian was a member of IAU (1970), EAS, French Society of Astronomy and Astrophysics (SF2A), and Romanian Academy of Sciences. In 2008 he was elected foreign member of the National Academy of Sciences of the Republic of Armenia and in 2009, member of the Armenian Astronomical Society (ArAS).


Zadig Mouradian deceased on January 22, 2020 in Paris.