Interaction of planetary nebulae, Eta-Carinae and supernova remnants
  with the Interstellar Medium
  The image of planetary nebulae (PN), supernova remnant (SNR) and Eta-Carinae
is made by three different physical processes. The first process is the
expansion of the shell that can be modeled by the canonical laws of motion in
the spherical case and by the momentum conservation when gradients of density
are present in the interstellar medium. The quality of the simulations is
introduced along one direction as well along many directions.
  The second process is the diffusion of particles that radiate from the
advancing layer. The 3D diffusion from a sphere, the 1D diffusion with drift
and 1D random walk are analyzed. The third process is the composition of the
image through an integral operation along the line of sight. The developed
framework is applied to three PN which are A39, the Ring nebula and the etched
hourglass nebula MyCn 18, the hybrid object Eta-Carinae, and to two SNR which
are SN 1993J and SN 1006. In all the considered cases a careful comparison
between the observed and theoretical profiles in intensity is done.
