Related papers: Kinematical Analysis of a Sample of Bipolar Planet…
Pulsars steadily dissipate their rotational energy via relativistic winds. Confinement of these outflows generates luminous pulsar wind nebulae, seen across the electromagnetic spectrum in synchrotron and inverse Compton emission, and in…
Starting from the Strasbourg ESO Catalogue (SEC) of Planetary Nebulae (PNe), the largest PNe compilation available with ~ 1500 objects, we undertook a comprehensive study of the whole PN population, never carried out so far, only using…
We search for very small-diameter galactic planetary nebulae (PNe) representing the earliest phases of PN evolution. A recently published IPHAS catalogue of Ha-emitting stars provides a useful base for this study as all sources present in…
The results of long-term spectral observations were used to search for changes in planetary nebulae and emission-line stars. Significant increase of excitation degree is found in two objects: M1-6 and M1-11.
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…
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…
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…
Using an [OIII]5007 on-band/off-band filter technique, we identify 109 planetary nebulae (PNe) candidates in M 82, using the FOCAS instrument at the 8.2m Subaru Telescope. The use of ancillary high-resolution HST ACS H-alpha imaging aided…
A review of recent observations of the kinematics of six objects that represent the broad range of phenomena called planetary nebulae (PNe) is presented. It is demonstrated that Hubble-type outflows are predominant, consequently it is…
Individual distances to planetary nebulae are of the utmost relevance for our understanding of post-asymptotic giant-branch evolution because they allow a precise determination of stellar and nebular properties. Also, objects with…
The Planetary Nebula Spectrograph is a dedicated instrument for measuring radial velocity of individual Planetary Nebulae (PNe) in galaxies. This new instrument is providing crucial data with which to probe the structure of dark halos in…
The age-velocity dispersion relation is an important tool to understand the evolution of the disc of the Andromeda galaxy (M31) in comparison with the Milky Way. We use Planetary Nebulae (PNe) to obtain the age-velocity dispersion relation…
We present high quality radio continuum observations made with the Very Large Array (VLA) at 3.6 cm at two epochs toward the planetary nebula M2-43. The comparison of the two epochs, obtained with a time separation of 4.07 years, clearly…
Once classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has been only recently recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we…
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 narrow-band near-infrared images of a sample of 11 Galactic planetary nebulae (PNe) obtained in the molecular hydrogen (H$_{2}$) 2.122 $\mu$m and Br$\gamma$ 2.166 $\mu$m emission lines and the $K_{\rm c}$ 2.218 $\mu$m continuum.…
Using two-dimensional hydrodynamical simulations, we investigate the interaction of a collimated fast wind (CFW) interacting with a spherical asymptotic giant branch (AGB) wind as the mechanism for shaping proto-planetary nebulae and young…
Eleven objects that have been reported as proto-planetary nebula or as young planetary nebulae that show very extended Halpha wings are presented. The extension of these wings is larger than 800 km/s. Data for two symbiotic stars that show…
We describe calculations of the evolution of an ensemble of small planetesimals in the outer solar system. In a solar nebula with a mass of several times the Minimum Mass Solar Nebula, objects with radii of 100-1000 km can form on…
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…