Dirk Coster
Dirk Coster (October 5, 1889 – February 12, 1950) was a Dutch physicist and professor of physics and meteorology at the University of Groningen. He is best known for co-discovering hafnium (element 72) in 1923 with George de Hevesy, using X-ray spectroscopy of zirconium ore. The element was named hafnium after Hafnia, the Latin name for Copenhagen, where the work took place. He also helped Lise Meitner escape from Nazi Germany.
Coster was born in Amsterdam into a large working‑class family. He trained as a teacher in Haarlem (1904–1908) and taught until 1913, then studied mathematics and physics at Leiden University, encouraged by Paul Ehrenfest, earning his MSc in 1916. He worked at Delft University of Technology and earned an electrical engineering degree in 1919. He researched X-ray spectroscopy at Lund University (1920–1921) and earned his PhD in Leiden in 1922 under Ehrenfest, with a thesis on X-ray spectra and Bohr’s theory.
From 1922 to 1923 he worked with Niels Bohr in Copenhagen, and soon after with Hevesy on hafnium. He then worked at the Teylers Museum in Haarlem before joining the University of Groningen in 1924, where he built an active X-ray spectroscopy program. He became a member of the Royal Netherlands Academy of Arts and Sciences in 1934.
Coster married Lina Maria Wijsman in 1919; they had four children. In 1938 he helped Lise Meitner escape Nazi Germany, transporting her to the Netherlands and then Sweden. During the German occupation he helped hide Jews and listened to the BBC on a bicycle-powered radio. He died in Groningen in 1950. The asteroid 10445 Coster is named after him.
This page was last edited on 2 February 2026, at 13:10 (CET).