Paul Ledoux

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Paul Ledoux
Born (1914-08-08)August 8, 1914
Forrières, Belgium
Died October 6, 1988(1988-10-06) (aged 74)
Liège, Belgium
Citizenship Belgian
Alma mater University of Liège
Known for
  • Ledoux criterion
Scientific career
Fields Astrophysics
Institutions University of Liège

Paul Ledoux (August 8, 1914 – October 6, 1988[2]) was a Belgian astrophysicist, best known for his work on stellar stability and variability. With Theodore Walraven, he co-authored one of the seminal works on stellar oscillations.[3] In 1964 Paul Ledoux was awarded the Francqui Prize for Exact Sciences. He was awarded the Eddington Medal of the Royal Astronomical Society in 1972[4] for investigations into problems of stellar stability and variable stars. He was awarded the Janssen Medal of the French Academy of Sciences in 1976.

Ledoux criterion[edit]

In stellar astrophysics, Ledoux's name is now associated with the criterion under which material in a star becomes unstable to convection in the presence of a gradient of chemical composition. In homogenous material, the Schwarzschild criterion shows that material is unstable to convection if the radiation field alone would establish a steeper temperature gradient steeper than the adiabatic (or isentropic) temperature gradient. However, Ledoux showed that a composition gradient stabilises or destabilises the material against convection.[5] In convectively-stable regions destabilised by the composition gradient, one expects thermohaline mixing; in convectively-unstable regions that are stabilised, one expects double-diffusive mixing, known in stellar astrophysics as semiconvection.


  1. ^ [1]
  2. ^ Swings, J. P. (1989), "Obituary - Ledoux Paul", Ap&SS, 155: 179, Bibcode:1989Ap&SS.155..179S 
  3. ^ Ledoux, P.; Walraven, T. (1958), "Variable Stars.", Handbuch der Physik, 51: 353, Bibcode:1958HDP....51..353L 
  4. ^ Hoyle, F. (1972), "P. Ledoux received the Eddington Medal.", QJRAS, 13: 348, Bibcode:1972QJRAS..13..485H 
  5. ^ Ledoux, P. (1947), "Stellar Models with Convection and with Discontinuity of the Mean Molecular Weight", The Astrophysical Journal, 105: 305, Bibcode:1947ApJ...105..305L, doi:10.1086/144905