Related papers: Shaping Planetary Nebulae and Related Objects
We analyse a large sample of galactic planetary nebulae based on their chemical composition and morphology. A recent morphological classification system is adopted, and several elements are considered, namely He, N, O, S, Ar, Ne, and C in…
Recent spectroscopic observations of planetary nebulae (PNe) in several elliptical galaxies have revealed structural and kinematical properties of the outer stellar halo regions. In order to elucidate the origin of the properties of these…
How galaxies formed and evolved in the expanding Universe is the main science goal of Near-Field Cosmology research. Studies of the properties of galaxies' resolved stars open a widow on their ancient galactic components, probing star…
Some of the correlations between morphological and other physical properties of planetary nebulae (PNe) are reviewed. In particular, the finding that bipolar (b) PNe have more massive progenitors than the other morphological classes is…
Multiple shell planetary nebulae (MSPNe) are most likely a consequence of the modulation of the mass-loss rate during the thermal pulses on the AGB. By using numerical simulations of their formation, the models' predictions and the history…
We describe how the large scale geometry of the circumstellar envelopes of asymptotic giant branch stars can be used to probe the presence of unseen stellar companions. A nearby companion modifies the mass loss by gravitationally focusing…
A significant fraction of planetary nebulae (PNe) and proto-planetary nebulae (PPNe) exhibit aspherical, axisymmetric structures, many of which are highly collimated. The origin of these structures is not entirely understood, however recent…
Using a radiation-hydrodynamics code I follow the formation of planetary nebulae around stars of different mass. Because a more massive central star evolves much faster than a lower mass one, it is to be expected that this will affect the…
Planetary Nebulae (PNe) have been used satisfactory to test the effects of stellar evolution on the Galactic chemical environment. Moreover, a link exists between nebular morphology and stellar populations and evolution. We present the…
I propose that some irregular `messy' planetary nebulae owe their morphologies to triple-stellar evolution where tight binary systems evolve inside and/or on the outskirts the envelope of asymptotic giant branch (AGB) stars. In some cases…
Using a radiation-gasdynamics code the evolution of spherical planetary nebulae is followed, while taking into account the evolution of central star and the fast wind. These models show the importance of ionization fronts for the structure…
We argue that relative to non-spherical planetary nebulae (PNs), spherical PNs are about an order of magnitude less likely to be detected, at distances of several kiloparsecs. Noting the structure similarity of halos around non-spherical…
Planetary Nebulae are the ionised ejected envelopes surrounding the remnant cores of dying stars. Theory predicts that main-sequence stars with one to about eight times the mass of our sun may eventually form planetary nebulae. Until now no…
Hydrodynamical simulations played an important role in understanding the dynamics and shaping of planetary nebulae in the past century. However, hydrodynamical simulations were just a first order approach. The new millennium arrived with…
The morphologies of planetary nebulae are believed to be self-organized configurations. These configurations are modeled by three-dimensional temporally self-similar magnetohydrodynamic solutions with radial flow, under the gravitational…
Using the Hubble Space Telescope (HST), we have carried out a survey of candidate preplanetary nebulae (PPNs). We report here our discoveries of objects having well-resolved geometrical structures, and use the large sample of PPNs now…
Planetary nebulae (PNe) are known to possess a variety of small-scale structures that are usually in a lower ionization state than the main body of the nebulae. The morphological and kinematic properties of these low-ionization structures…
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…
In this paper we explore the dynamics of ionization bounded planetary nebulae after the termination of the fast stellar wind. When the stellar wind becomes negligible, the hot, shocked bubble depressurizes and the thermal pressure of the…
Many binary companions to the central stars of planetary nebulae (PNe) are found to be inflated, perhaps indicating that accretion onto the central star might occur during the PN phase. The discovery of a handful of nova eruptions and…