Albrecht Unsöld

Albrecht Otto Johannes Unsöld (20 April 1905 – 23 September 1995) was a German astrophysicist known for his contributions to spectroscopic analysis of stellar atmospheres.

[1] As a Fellow of the Rockefeller Foundation, he was an assistant in Potsdam and worked at the Mount Wilson Observatory in Pasadena, California.

In September 1932, Unsöld became Ordinarius Professor and Director of the Institute for Theoretical Physics (and Observatory) at the University of Kiel – a position he held until his emeritus status was granted in 1973, after which he remained scientifically active for 15 years.

[6][7][8] Unsöld's theorem states that the square of the total electron wavefunction for a filled or half-filled sub-shell is spherically symmetric.

At Kiel, Unsöld made an intensive study of the effects of abundances, radiation damping, Doppler shifts, electric fields, and collisions on the formation and shape of spectral lines in stellar atmospheres.