Hans Albrecht Bethe (1906-2005), a German physicist noted for his discovery of the reactions that supply the energy of stars. After the rise of Nazis in Germany, Bethe immigrated to England in 1933 where he held teaching positions at the University of Manchester and the University of Bristol. In 1935, Bethe received the position of Assistant Professor at Cornell University. During the years 1935-1939, Bethe's main achievement in astrophysics was the exclusion of the many possible interactions than can happen inside the stars, leaving just two possibilities for which were providing the stars with energy: the carbon-nitrogen cycle for massive stars, and the proton-proton reaction that powers fainter stars like the Sun. Bethe was awarded the Nobel Prize for Physics in 1967.
Hans Bethe-Biography (Nobel Prize Biographies)
Personal and Historical Perspectives of Hans Bethe (Cornell University)