3D hydrodynamical models of point-symmetric planetary nebulae: the special case of H 1-67

Abstract

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 analysed at times up to 1500 or 1800 yr. From our hydrodynamical models, we obtain position-velocity diagrams (PV diagrams) in the [N II] λ6583 line to be compared with high-resolution observations of the planetary nebula H 1-67. 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°. Our synthetic PV diagrams can be used to understand how the S-like morphology, also presented by other planetary nebulae, is formed. For H 1-67, we found a heliocentric velocity of -8.05 km s^-1 and height below the galactic plane of -451.6 pc.