Bengt Georg Daniel Strömgren

Bengt Georg Daniel Strömgren


Date of Birth
January 21, 1908
Date of Death
July 4, 1987

Bengt Strömgren, the son of the director of the Copenhagen University Observatory, had published many research papers—mostly in celestial mechanics— and coauthored one book by the time he received his Ph.D. from the University of Copenhagen at age 21. After working there and at the Yerkes Observatory he succeeded his father at Copenhagen in 1940. He was director of Yerkes and McDonald Observatories from 1951 to 1957 and spent ten years at the Institute for Advanced Study in Princeton before returning to Copenhagen University and the Nordic Institute for Theoretical Physics (NORDITA). Strömgren did important research in stellar structure in the 1930s, but he is best known for his theory of the ionized gas clouds around hot stars. He found relations between the gas density, the luminosity of the star, and the size of the “Strömgren sphere” of ionized hydrogen around it. He surveyed such H II regions in the Galaxy, and he also did important work on stellar atmospheres and ionization in stars. He calculated the relative abundances of the elements in the sun and other stars and worked on optical design and, for many years, on the development of photoelectric photometry.

Presentation of Bruce medal

Mayall, N.U., PASP 71, 79 (1959).

Other awards

American Astronomical Society, Henry Norris Russell Lectureship, 1965.
Association pour le Développement International de Astronomische Gesellschaft, Karl Schwarzschild Medal, 1969.
Royal Astronomical Society, Gold medal, 1962, presented by W.H. McRae, QJRAS 3, 81-83 (1962).

Some offices held

American Astronomical Society, President, 1966-67.
International Astronomical Union, President, 1970-73; General Secretary, 1948-52.

Biographical materials

Cayrel, Roger, “La vie et l’oeuvre de Bengt Strömgren,” Comptes Rendus de l’Académie des Sciences: La Vie des Sciences 6, 609-610 (1989).
Rebsdorf, Simon Olling, “Bengt Strömgren: Growing Up With Astronomy, 1908–1932,” Journal for the History of Astronomy 34, 171-99 (2003).
Rebsdorf, Simon Olling, The Father, the Son, and the Stars: Bengt Strömgren and the History of Twentieth Century Astronomy in Denmark and in the USA (Ph.D. dissertation, University of Aarhus, 2004; LAP Lambert Acad. Publ., 2010).
Rebsdorf, Simon Olling, “Bengt Strömgren: Interstellar Glow, Helium Content, and Solar Life Supply, 1932–1940,” Centaurus 49, 56-79 (2007).
Rebsdorf, Simon Olling, Bengt Strömgren’s life among the stars, Niels Bohr Institute website.
Strömgren, B., “Scientists I have Known and Some Astronomical Problems I Have Met,” Ann. Rev. Astron. Astrophys. 21, 1-11 (1983).


Spitzer, Lyman, Jr., Physics Today 41, no. 3, 112, 114 (1988).
Rudkjobing, M., QJRAS 29, 282 (1988).
Sky & Telescope 74, 348 (1987).


AIP Center for History of Physics Library of Congress Prints and Photographs Division. New York World-Telegram and the Sun Newspaper Photograph Collection

Named after him

Minor planet #1846 Bengt
Strömgren Sphere


Papers, etc.

There are oral history interviews taken in 1976 and 1978 at the Niels Bohr Library & Archives.

Other References: Historical

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Arny, Thomas, “The Star Makers: a History of the Theories of Stellar Structure and Evolution,” Vistas in Astronomy 33, 2, 211-33 (1990).

Cowling, Thomas, “The Development of the Theory of Stellar Structures,” QJRAS 7, 121-37 (1966).

Gustafsson, Bengt, “Bengt Strömgren’s Approach to the Galaxy,” in J. Andersen, J. Bland-Hawthorn & B. Nordström, eds., The Galaxy Disk in Cosmological Context. Proceedings IAU Symposium No. 254 (Cambridge Univ. Press, 2009), pp. 3-16.

Knude, Jens, ”Bengt Stromgren's Work in Photometry,” in A.G.D. Philip, A.R. Upgren and K.A. Janes, eds., Precision Photometry: Astrophysics of the Galaxy, Proceedings of the conference held 3-4 October, 1990 at Union College, Schenectady, NY (Davis Press, Schenectady, NY, 1991).

Osterbrock, Donald E., Yerkes Observatory 1892-1950: The Birth, Near Death, and Resurrection of a Scientific Research Institution (Univ. of Chicago Press, Chicago, 1997).

Strömgren, Bengt, “The Rise of Astrophysics,” Annals NY Acad. Sci. 198, 245-54 (1972).

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Other References: Scientific

Search ADS for works by Strömgren


Nissen, P.E., “Bibliography—Bengt Strömgren,” in Astrophysics: Recent Progress and Future Possibilities. Invited Reviews at a Symposium in Honour of Bengt Stromgren [1908-1987] held in Copenhagen, May 25-26, 1988, B. Gustafsson & P.E. Nissen, eds. (The Royal Danish Academy of Science and Letters, Copenhagen, 1990), p. 9.

Reiz, A. & T. Andersen, eds., Astronomical Papers Dedicated to Bengt Strömgren, Presented at a Symposium Held in Copenhagen, May 30-June 1, 1978 (Copenhagen University Observatory, Copenhagen, 1978?).

Strömgren, B. “Bestimmung der RA von 131 polnahen Sternen. nach Beobachtungen in den Jahren 1921 - 1923 angestellt am Repsoldschen Durchgangsinstrument der Kopenhagener Sternwarte,” Publ. og mindre Medd. fra Koebenhavns Obs. 50, 12-15 (1925).

Strömgren, Bengt, “Die Ionisation in den Atmospheären der Himmelskörper,” Handbuch der Astrophysik 7, 203 (1936).

Strömgren, Bengt, “Thermodynamik der Sterne und Pulsationstheorie,” Handbuch der Astrophysik 7, 212 (1936).

Strömgren, Bengt, “The Physical State of Interstellar Hydrogen,” Ap.J. 89, 526-47 (1939). [reprinted in the centennial edition Ap.J. 525C, 299 (1999) with a modern commentary by C.R. O’Dell]


Stromgren, Elis, Bengt Stromgren, Nikolai Fedorovich Bulaevskii, & S.Shorygin, Astronomiia (1941) [in Russian].

Strömgren, Bengt, “2-Dimensional Spectral Classification of F Stars through Photoelectric Photometry with Interference Filters,” Vistas in Astronomy 2, 1336-45 (1957).

Other Works: Popularizations, History, etc.

Strömgren, Ellis & Bengt, Lehrbuch der Astronomie (Springer, Berlin, 1933).

Strömgren, Bengt, Universets Udforskning (Hirschsprung, Copenhagen, 1940, 1945, 1955).

Strömgren, Bengt, Address in Commemoration of the Fourth Centenary of the Birth of Tycho Brahe 14th of December, 1946 (1946).

Strömgren, Bengt, “The Development of Astrophysics as a Research Field in the 20th Century: Paper Presented at the American Association for the Advancement of Science’s George Ellery Hale Centennial Symposium, Dallas, 1968” available at the Niels Bohr Library & Archives.