Related papers: Spherical Planetary Nebulae
The study of planetary nebulae (PNe) offers the opportunity of evaluating the efficiency of the dust production mechanism during the very late asymptotic giant branch (AGB) phases. We study the relationship between the properties of PNe,…
Planetary nebulae (PNe) constitute an important tool to study the chemical evolution of the Milky Way and other galaxies, probing the nucleosynthesis processes, abundance gradients and the chemical enrichment of the interstellar medium. In…
The kinematic structure of a sample of planetary nebulae, consisting of 23 [WR] central stars, 21 weak emission line stars (wels) and 57 non-emission line central stars, is studied. The [WR] stars are shown to be surrounded by turbulent…
Planetary Nebulae (PNe) are the result of heavy mass loss of the asymptotic giant branch (AGB) stars. They are understood in terms of Kwok's (1978) interacting-winds model as the product of the mass-loss history on the AGB and the central…
We present a homogeneous set of spectroscopic measurements secured with 4-meter class telescopes for a sample of 90 planetary nebulae (PNe) located in the direction of the Galactic bulge. We derive their plasma parameters and chemical…
Planetary Nebulae represent a powerful window into the evolution of low-intermediate mass stars that have undergone extensive mass-loss. The nebula manifests itself in an extremely wide variety of shapes, but exactly how the mass lost is…
The correlations between planetary nebula (PN) morphology and the nature of their progenitors are explored by examining homogeneous PN samples in the Galaxy and the Magellanic Clouds. We selected PNe with reliable abundances from spectral…
The recent HST optical images, and the optical and ultraviolet spectra, of Magellanic planetary nebulae (PNe), together with the large data-base that has been collected in the past decade, allows unprecedented insight in the evolution of…
I list the 16 planetary nebulae (PNe) known to contain close-binary nuclei, and show that the nebulae generally have axisymmetric structures, including elliptical, bipolar, or ring morphologies. The orbital periods range from 2.7 hr to 16…
We present spectroscopy of nine planetary nebulae (PNe) in the outskirts of M31, all but one obtained with the 10.4m GTC telescope. These sources extend our previous study of the oxygen abundance gradient of M31 to galactocentric radii as…
Low- and intermediate-mass ($\rm 0.8~M_\odot < M < 8~M_\odot$) stars that evolve into planetary nebulae (PNe) play an important role in tracing and driving Galactic chemical evolution. Spectroscopy of PNe enables access to both the initial…
Based on published data, we have produced a sample of planetary nebulae (PNe) that is complete within 2 kpc of the Sun. We have estimated the total number of PNe in the Galaxy from this sample to be 17000+/-3000 and determined the vertical…
We investigate the galactic disk distribution of a sample of planetary nebulae characterised in terms of their mid-infrared spectral features. The total number of galactic disk PNe with 8-13mum spectra is brought up to 74 with the inclusion…
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…
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…
Most planetary nebulae (PNe) show beautiful, axisymmetric morphologies despite their progenitor stars being essentially spherical. Close binarity is widely invoked to help eject an axisymmetric nebula, after a brief phase of engulfment of…
Extra-galactic planetary nebulae (PNe) permit the study of dust and molecules in metallicity environments other than the Galaxy. Their known distances lower the number of free parameters in the observations vs. models comparison, providing…
Spectroscopic data of two relatively [O III]-luminous-PNe have been obtained with the 10.4-m Gran Telescopio Canarias. M174 and M2496 are each ~1 degree from the center of M31 along opposite sides of its minor axis. The ensemble of these…
We derive abundances and central star parameters for 15 planetary nebulae (PNe) in M31: 12 in the bulge and 3 in a disk field 14 kpc from the nucleus. No single abundance value characterizes the bulge stars: although the median abundances…
Astrophysical outflows treated initially as spherically symmetric often show evidence for asymmetry once seen at higher resolution. The preponderance of aspherical and multipolar planetary nebulae (PN) and pre-planetary nebulae (PPN) was…