SHAPING THE RED RECTANGLE PROTO-PLANETARY NEBULA BY A PRECESSING JET

We carried out three-dimensional hydrodynamical simulations (employing the YGUAZU-A code) of a precessing jet launched by a star in a binary system. Synthetic scattered light intensity maps were generated in order to compare them with images of the Red Rectangle proto-planetary nebula (PPN), which contains the binary system HD 44179. Our results show that the angular size, the global biconical or hourglass morphology, and the existence of its ladder rungs features can be explained in terms of a jet precessing with a period 20 times the orbital period of the HD 44179 system, a semi-angle of 30 degrees (of the precession cone), and a velocity of 300 km s(-1). In addition, we calculated the flux predicted from the models, which is of the same order of magnitude as the observed flux in the outer regions of the nebula. Finally, the orbital motion was found to have a negligible influence on the large-scale morphology of the PPN.