Related papers: Fallback in bipolar Planetary Nebulae ?
Observations suggest that many, if not all, post AGB systems evolve through an aspherical outflow phase. Such outflows require a sufficient engine rotational energy which binaries can provide. Via common envelope evolution, binaries can…
The morphology of bipolar planetary nebulae (PNe) can be attributed to interactions between a fast wind from the central engine and dense toroidal shaped ejecta left over from common envelope (CE) evolution. Here we use the 3-D hydrodynamic…
Young planetary nebulae play an important role in stellar evolution when intermediate- to low-mass stars (0.8 ~ 8 M) evolve from the proto-planetary nebulae phase to the planetary nebulae phase. Many young planetary nebulae display distinct…
The young planetary nebulae play an important role in stellar evolution when intermediate- to low-mass stars (0.8 $\sim$ 8 M$_\odot$) evolve from the proto-planetary nebulae phase to the planetary nebulae phase. Many young planetary nebulae…
A large class of stellar systems (e.g., planetary nebulae (PNe), supernova envelopes, LBV stars, young stars in formation) shows structures in their accretion/ejection phase that have similar characteristics. In particular, one currently…
Since various structural components of planetary nebulae manifest themselves differently, a combination of optical, infrared, submm, and radio techniques is needed to derive a complete picture of planetary nebulae. The effects of projection…
We simulate the formation of bipolar planetary nebulae (PNe) through very short impulsive mass ejection events from binary systems, where the asymptotic giant branch (AGB) star ejects a mass shell that is accelerated by jets launched from a…
Planetary nebulae (PNe) can be roughly categorized into several broad morphological classes. The high quality images of PNe acquired in recent years, however, have revealed a wealth of fine structures that preclude simplistic models for…
Some fraction of the material ejected in a core collapse supernova explosion may remain bound to the compact remnant, and eventually turn around and fall back. We show that the late time (> days) power associated with the accretion of this…
The morphology of planetary nebulae emerging from the common envelope phase of binary star evolution is investigated. Using initial conditions based on the numerical results of hydrodynamical simulations of the common envelope phase it is…
Considerable effort has been applied towards understanding the precise shaping mechanisms responsible for the diverse range of morphologies exhibited by planetary nebulae (PNe). A binary companion is increasingly gaining support as a…
We present a visible-infrared imaging study of young planetary nebula (PN) Hubble 12 (Hb 12; PN G111.8-02.8) obtained with Hubble Space Telescope (HST) archival data and our own Canada-France-Hawaii Telescope (CFHT) measurements. Deep HST…
Hypersonic bipolar outflows are a ubiquitous phenomena associated with both young and highly evolved stars. Observations of Planetary Nebulae, the nebulae surrounding Luminous Blue Variables such as $\eta$ Carinae, Wolf Rayet bubbles, the…
We present near-IR K-band intermediate-dispersion spatially-resolved spectroscopic observations of a limited sample of bipolar planetary nebulae (PNe). The spectra have been used to determine the excitation mechanism of the H2 molecule…
Bipolar planetary nebulae (PNe) are thought to result from binary star interactions and, indeed, tens of binary central stars of PNe have been found, in particular using photometric time-series that allow detecting post-common envelope…
The majority of Proto-planetary nebulae (PPN) are observed to have bipolar morphologies. The majority of mature PN are observed to have elliptical shapes. In this paper we address the evolution of PPN/PN morphologies attempting to…
There is a growing number of observational indicators for the presence of bipolar outflows in massive, young stellar objects that are still accreting mass as part of their formation process. In particular, there is evidence that the…
This work presents three dimensional, magneto-hydrodynamical simulations of the formation and early evolution of a subgroup of planetary nebulae that exhibit a variety of point-symmetric structures. For bipolar nebulae, the formation of…
While in the past spheroidicity was assumed, and still is used in modeling of most nebulae, we know now that only a small number of planetary nebulae (PNe) are really spherical or at least nearly round. Round planetary nebulae are the…
Studying the appearance and properties of bipolar winds is critical to understand the stellar evolution from the AGB to the planetary nebula (PN) phase. Many uncertainties exist regarding the presence and role of binary stellar systems,…