Bengt Stromgren

Bengt Stromgren was a Danish astronomer and astrophysicist who discovered that regions of ionized hydrogen gas surrounding hot young stars form sharply bounded interstellar shells, now called Stromgren spheres. He also showed that the Sun and similar stars are composed mostly of hydrogen and helium, roughly seventy percent hydrogen and twenty seven percent helium, correcting earlier assumptions about stellar composition, and he pioneered a system of photoelectric photometry known as the Stromgren photometric system. The son of the astronomer Elis Stromgren, he published his first scientific paper at age fourteen and earned his doctorate at twenty one in 1929. He worked at the University of Chicago under Otto Struve from 1936 to 1938, succeeded his father as professor at the University of Copenhagen in 1940, directed the Yerkes and McDonald Observatories from 1951 to 1957, and became the first professor of theoretical astrophysics at the Institute for Advanced Study in Princeton in 1957, occupying Albert Einstein former office, before returning to Denmark in 1967. He received the Bruce Medal in 1959 and the Gold Medal of the Royal Astronomical Society in 1962.