On chaotic behavior of gravitating stellar shells
  Motion of two gravitating spherical stellar shells around a massive central body is considered. Each shell consists of point particles with the same specific angular momenta and energies. In the case when one can neglect the influence of gravitation of one ("light") shell onto another ("heavy") shell ("restricted problem") the structure of the phase space is described. The scaling laws for the measure of the domain of chaotic motion and for the minimal energy of the light shell sufficient for its escape to infinity are obtained. 
M.V. Barkov, G.S. Bisnovatyi-Kogan, A.I. Neishtadt and V.A. Belinski