New Observations of the High-Velocity Outflows of the Proto-Planetary Nebula Hen 3-1475

Abstract

The proto-planetary nebula Hen 3-1475 shows a remarkable highly collimated optical jet with a S-shaped string of shock-excited knots. Moreover, extremely high velocities have been observed in the innermost regions of its jet. We present a detailed analysis of the kinematic structure, and the excitation conditions in the shock-excited knots based on ground-based high dispersion spectroscopy and high angular resolution images obtained with the HST WFPC2. We discuss the similarities between the jet of Hen 3-1475 and the HH jets. Both exhibit double-peaked and extremely wide profiles, a decrease of the radial velocities with distance to the source in a step-like fashion, and high tangential velocities. The overall picture of Hen 3-1475 supports the description of the system as the result of time-dependent ejection velocity variability.