The Bruce Medalists


  portrait Photo ca. 1956, courtesy Prof. Unsöld
Albrecht Otto Johannes Unsöld
20 April 1905 1956 Bruce Medalist 23 September 1995

Albrecht Unsöld studied quantum mechanics under Arnold Sommerfeld at the University of Munich and began working on stellar atmospheres in 1927. He spent nearly his entire career at the University of Kiel, where he was appointed professor in 1932. By intensive study of the processes influencing the formation and shape of spectral lines — the effects of abundances, radiation damping, Doppler shifts, electric fields, and collisions — he greatly improved the methods of determining physical conditions in stellar atmospheres. Unsöld's analysis of the spectrum of the B0 star Tau Scorpii, obtained on a 1939 visit to Yerkes and McDonald Observatories, provided the first detailed analysis of a star other than the sun. From it he determined the physics and composition of the star’s atmosphere. He wrote an influential book on stellar atmospheres, edited the Zeitschrift für Astrophysik until it was merged with other European journals into Astronomy and Astrophysics, and educated many important astronomers.

Presentation of Bruce medal
Wilson, O.C., PASP 68, 89-91 (1956).

Other awards
Royal Astronomical Society, Gold medal, 1957, presented by H. Jeffreys, MNRAS 117, 344-46 (1957)

Some offices held
Astronomische Gesellschaft, President, 1947-48.

Biographical materials
Weidemann, Volker, Christian-Albrechts-Universität zu Kiel [in German]
Modern Scientists and Engineers (McGraw-Hill, NY, 1980).

Baschek, Bodo, Mitteilungen der Astronomische Gesellschaft 79, 11-15, (1996) [in German].
Seaton, Mike, Astronomy & Geophysics 38, 1, 37-38 (1997).
Wiedemann, Volker, PASP 108, 553-55 (1996).

AIP Center for History of Physics

Named after him
Minor planet #2842 Unsöld

More references

The Bruce Medalists

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