3D hydrodynamical models of point-symmetric planetary nebulae: the
  special case of H1-67
  We present 3D hydrodynamical simulations of a precessing jet with a
time-dependent ejection velocity or a time-dependent ejection density,
interacting with a circumstellar medium given by a dense, anisotropic, and slow
AGB wind, forming a torus. We explore a set of configurations with different
values for the precession angle and number of ejections. The temporal evolution
of these models is analised at times up to 1500 or 1800 yr. From our
hydrodynamical models, we obtain position-velocity diagrams (PV diagrams) in
the [NII]{\lambda}6583 line to be compared with high resolution observations of
the planetary nebula H1-67. From spectral data this object shows high-velocity
jets and a point-symmetric morphology. With our synthetic PV diagrams we show
that a precessing jet with a time-dependent ejection velocity or a
time-dependent ejection density reproduce the point-symmetric morphological
structure for this nebula if the precession cone angle is larger than
30$^{\circ}$. Our synthetic PV diagrams can be used to understand how the
S-like morphology, also presented by other planetary nebulae, is formed. For
H1-67 we found a heliocentric velocity of -8.05 km s^-1 and height below the
galactic plane of -451.6 pc.
