Abstract
The morphologies of planetary nebula have long been believed to be due to wind shaping processes in which a “fast wind” from the central star impacts a previously ejected envelope. It is assumed that asymmetries existing in the “slow wind” envelope would lead to inertial confinement, shaping the resulting interacting wind flow. We present new results demonstrating the effectiveness of Common Envelope Evolution (CEE) at producing aspherical envelopes which, when impinged upon by a spherical fast stellar wind, produce highly bipolar, jet-like outflows. We have run two simple cases using the output of a single PHANTOM SPH CEE simulation. Our work uses the Adaptive Mesh Refinement code AstroBEAR to track the interaction of the fast wind and CEE ejecta allows us to follow the morphological evolution of the outflow lobes at high resolution in 3-D. Our two models bracket low and high momentum output fast winds. We find the interaction leads to highly collimated bipolar outflows. In addition, the bipolar morphology depends on the fast wind momentum injection rate. With this dependence comes the initiation of significant symmetry breaking between the top and bottom bipolar lobes. Our simulations, though simplified, confirm the long-standing belief that CEE can plan a major role in PPN and PN shaping. These simulations are intended as an initial exploration of the post-CE/PPN flow patterns that can be expected from central source outflows and CE ejecta.
Highlights
Planetary nebulae (“PN”) are formed via gas ejected from highly evolved stars starting within a few thousand years before their final state as white dwarfs
In this Generalized Interacting Stellar Wind model (GISW), the run from mildly elliptical PN to strongly bipolar “butterfly” shaped nebula depends on the pole-to-equator density contrast in the AGB slow wind (e = ρp /ρe ) and its aspherical morphology
Using the full Common Envelope Evolution (CEE) simulations as input, we have performed AMR simulations that track the interaction of a fast wind from a central source and a strongly aspherical CEE
Summary
Planetary nebulae (“PN”) are formed via gas ejected from highly evolved stars starting within a few thousand years before their final state as white dwarfs. Once a spherical fast wind begins impinging on this aspherical slow wind, “inertial confinement” leads the resulting shocks to take on the elliptical or bipolar configurations In this Generalized Interacting Stellar Wind model (GISW), the run from mildly elliptical PN to strongly bipolar “butterfly” shaped nebula depends on the pole-to-equator density contrast in the AGB slow wind (e = ρp /ρe ) and its aspherical morphology. New observations indicated that much of the shaping process for PN may occur before the central star heats up enough to produce ionizing radiation (the post-AGB/PPN phases [11]) While this recognition, along with the other mechanisms such as MHD, have contributed greatly to the understanding of PN shaping, the GISW model often remains in the background. Our goal in these initial studies is to map out the basic flow patterns emerging from GISW interactions with CEE initial conditions, using fully 3-D, high-resolution simulations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
