Related papers: Current Unsolved Problems in Planetary Nebulae Res…

It is now clear that a binary pathway is responsible for a significant fraction of planetary nebulae, and the continually increasing sample of known central binaries means that we are now in a position to begin to use these systems to…

Galaxies represent the visible fabric of the Universe and there has been considerable progress recently in both observational and theoretical studies. The underlying goal is to understand the present-day diversity of galaxy forms, masses…

We carefully consider numerous explanations for the sulfur abundance anomaly in planetary nebulae. No one rationale appears to be satisfactory, and we suggest that the ultimate explanation is likely to be a heretofore unidentified feature…

The question of what physical mechanisms shape planetary nebulae into their observed morphologies remains open. However, intensified efforts since the last meeting in this series, Asymmetrical Planetary Nebulae IV, in July 2007 have yielded…

During the past 20 years, the idea that non-spherical planetary nebulae (PN) may need a binary or planetary interaction to be shaped was discussed by various authors. It is now generally agreed that the varied morphologies of PN cannot be…

The total number of true, likely and possible planetary nebulae (PN) now known in the Milky Way is nearly 3000, double the number known a decade ago. The new discoveries are a legacy of the recent availability of wide field, narrowband…

In this paper, we will focus on the advances made in the last few years regarding the abundance discrepancy problem in ionized nebulae. We will show the importance of collecting deep, high-quality data of H II regions and planetary nebulae…

Planetary nebulae (PNe) exist in a range of different morphologies, from very simple and symmetric round shells, to elliptical, bipolar, and even quadrupolar shapes. They present extremely complex ensembles of filaments, knots, ansae, and…

Electron temperatures, densities, ionic and elemental abundances of helium, nitrogen, oxygen, argon, sulfur and neon were derived for a sample of bulge planetary nebulae, representative of its intermediate mass population. Using these…

This paper presents a homogeneous study of abundances in a sample of 79 northern galactic planetary nebulae whose morphological classes have been uniformly determined. Ionic abundances and plasma diagnostics were derived from selected…

The discovery of collimated outflows associated to point-symmetric features in Planetary Nebulae has proliferated in recent years. The systematic variation of radial velocity that many of them show strongly suggests a uniform rotation or…

In view of their nature, planetary nebulae have very short lifetimes, and the chemical abundances derived so far have a natural bias favoring younger objects. In this work, we report physical parameters and abundances for a sample of old…

Ionized nebulae are key to understanding the chemical composition and evolution of the Universe. Among these nebulae, H~{\sc ii} regions and planetary nebulae are particularly important as they provide insights into the present and past…

Planetary nebulae (PNe) have diverse morphological shapes, including point-symmetric and multipolar structures. Many PNe also have complicated internal structures such as torus, lobes, knots, and ansae. A complete accounting of all the…

Context: In recent years mid- and far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these…

Only a handful of binary central stars of planetary nebulae (PNe) are known today, due to the difficulty of detecting their companions. Preliminary results from radial velocity surveys, however, seem to indicate that binarity plays a…

Studies of the relationship between planetary nebula morphology and the evolution of the central stars has long suffered from uncertainties in distance determinations, and from the bias of interstellar absorption, that are typical for…

Close binary central stars of planetary nebulae are key in constraining the poorly-understood common-envelope phase of evolution, which in turn is critical in understanding the formation of a wide-range of astrophysical phenomena (including…

This review contains: (1) the scientific motivations for studying Planetary Nebulae in the Magellanic Clouds; (2) a review of this field of study, from the origins to the most recent results, focusing on the papers that have been published…

Why 80% of planetary nebulae are not spherical is not yet understood. The Binary Hypothesis states that a companion to the progenitor of the central star of a planetary nebula is required to shape the nebula and even for a planetary nebula…