We have investigated the infrared properties of a sample of objects with IRAS colors typical of planetary nebulae. The selected objects have not yet evolved to the planetary nebula stage since they have no detectable radio continuum emission and they are therefore likely postAGB stars.

The discovery of the " 21 " µm and " 30 " µm emission features in Planetary Nebulae with Wolf-Rayet central stars ⋆ Abstract. We report the discovery of the " 21 " µm and " 30 " µm features in the planetary nebulae around the hydrogen-deficient stars HD 826 and HD 158269. The carriers of these features are known to be produced in outflows around carbon-rich stars. This discovery demonstrates th...

We report the discovery, by the Chandra X-ray Observatory, of X-ray emission from the bipolar planetary nebula Menzel 3. In Chandra CCD imaging, Mz 3 displays hot (∼ 3 − 6 × 10 K) gas within its twin, coaxial bubbles of optical nebulosity, as well as a compact X-ray source at the position of its central star(s). The brightest diffuse X-ray emission lies along the polar axis of the optical nebul...

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 since the last IAU Symposium on Planetary Nebulae; (3) a review of the Hubble contribution to the field, from the early results to our own Magellanic Cloud P...

In a recent work Ciardullo et al. (1999) list 19 planetary nebulae surveyed by the Hubble Space Telescope for the presence of resolved visual binary companions of their central stars. For ten planetary nebulae they argue for probable physical association of the resolved stars with the central stars, while for nine the association is less likely. Such stellar companions, at orbital separations o...

We present high angular resolution observations of the NH3(1,1), (2,2) and (3,3) inversion transitions from the Egg Nebula, the archetypical proto-planetary nebula. The spatial distribution and kinematics of the emission in all three lines show four distinct components or lobes that are aligned with the polar and equatorial directions. The kinematics of the NH3 emission is also found to follow ...

By analogy with the minimum-mass solar nebula, we construct a surfacedensity profile using the orbits of the 26 precise-Doppler planets found in multiple-planet systems: Σ = 2200 g cm (a/1 AU), where a is the circumstellar radius and β = 2.0 ± 0.5. The minimum-mass solar nebula (β = 1.5) is consistent with this model, but the uniform-α accretion disk model (β ≈ 1) is not. In a nebula with β > 2...

We present Hα, [NII] and [OIII] ground-based and HST archive images, VLA–A 3.6 cm continuum and H92α emission line data and high resolution long-slit [NII] spectra of the planetary nebula Hu 2-1. A large number of structural components are identified in the nebula: an outer bipolar and an inner shell, two pairs of collimated bipolar structures at different directions, monopolar bow-shock-like s...

We report the first results of spectro-imaging postAGB objects in the near-infrared K’-band using a new instrument calledBEAR. This instrument has been used to obtain high spatial (0.6′′) and spectral (∼ 40 km s−1) resolution observations of the proto-planetary nebula AFGL 2688 and the young planetary nebula NGC 7027. The current paper is devoted to a detailed study of the morphology, velocity ...