Yusuke Hagiwara

Astronomer. Pioneer of celestial mechanics in Japan. Born in Osaka City. In 1921 (Taisho 10), he graduated from the Department of Astronomy, Faculty of Science, Tokyo Imperial University, and immediately became an assistant in the astronomy classroom and a technician at the Tokyo Astronomical Observatory. He received instruction in celestial mechanics from Hirayama Kiyotsugu, and was promoted to assistant professor in 1923. He then studied in Europe and the United States for two years, where he became familiar with lectures by Eddington and Birkhoff, and cultivated the foundations of theoretical astronomy. In 1930 (Showa 5) he received his doctorate for research into the dynamic stability of the solar system, and in 1935 he became a professor and engineer, and in 1944 he became a member of the Academy of Sciences, and in 1946 (Showa 21) he became director of the Observatory. During his tenure as director, he worked hard to establish two affiliated observatories, the Norikura Corona Observatory (opened in 1949) and the Okayama Astrophysical Observatory (opened in 1960), and he also devoted his energy to radio astronomy, laying the foundations for what would later become the Nobeyama Radio Observatory. In 1954, he was awarded the Order of Culture. After retiring from the University of Tokyo in 1957, he served as professor at Tohoku University and president of Utsunomiya University. He held many important positions, including vice-president of the International Astronomical Union. His books include the classic "Fundamentals of Celestial Mechanics" (1976), and he is also well known for his papers on quantum mechanical research into planetary nebulae.

[Shimamura Fukutaro July 19, 2017]

"The Fundamentals of Celestial Mechanics" (1976, Production Technology Center)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

天文学者。日本の天体力学の先駆者。大阪市に生まれる。1921年（大正10）東京帝国大学理学部天文学科卒業と同時に天文学教室助手兼東京天文台技手となる。平山清次(きよつぐ)に天体力学の指導を受け、1923年助教授昇進と同時に2年間欧米へ留学し、エディントンやバーコフの講義に親しみ、理論天文学の素地を培う。1930年（昭和5）太陽系の力学的安定性に関する研究で学位を得、1935年教授兼技師となり、1944年学士院会員、1946年（昭和21）天文台長に就任した。台長在任中、乗鞍(のりくら)コロナ観測所（1949年開設）、岡山天体物理観測所（1960年開設）の二つの付属観測所の設立に努力し、また電波天文学に熱意を注ぎ、のちの野辺山(のべやま)の宇宙電波観測所の基礎を固めた。1954年文化勲章受章。1957年東京大学退職後も東北大学教授、宇都宮大学学長を歴任。国際天文学連合副会長はじめ多くの要職についた。著書に名著『天体力学の基礎』（1976）があり、惑星状星雲の量子論的研究に関する論文などもよく知られる。

［島村福太郎　2017年7月19日］

『『天体力学の基礎』（1976・生産技術センター）』

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