SHOCK MODELING OF NEBULAE

The kinematics of Planetary Nebulae are analyzed in terms of the solut ions to the equations of hydrodynamic equilibrium developed by J. Cant o. We apply our analysis to the Planetary Nebulae NGC 6905 and NGC 653 7. A detailed spectroscopic study of these objects reveals the existen ce of high nuclear velocities, together with complex kinematic structu res and unusual emission line intensities. Shock ionization clearly pl ays a key role in these nebulae. Remarkably good agreement is obtained when comparing the synthetic maps and spectra resulting from the shoc k solutions with the observational data.