The virial theorem and the dynamics of supernovae

The use of the transformation groups leads to dynamical solutions of the no nlinear. gravitational hydrodynamical equations. These solutions, combined with the virial theorem, generalise the Chandrasekhar's static relation bet ween the total and the internal energies. The new relations describe a coll apse, an expansion or the sequence collapse/expansion of the external layer s of a star (case of a supernova, for example). (C) 2000 Academie des scien ces/Editions scientifiques et medicales Elsevier SAS.