Spectroscopic observations of 48 emission-line objects of M 33 have been obtained with the multi-object, wide field, fibre spectrograph AF2/WYFFOS at the 4.2 m...
Spectroscopy of six highly evolved Abell planetary nebulae
We have undertaken visual spectroscopy of the highly evolved planetary nebulae (PNe) A8, A13, A62, A72, A78 and A83 over a wavelength range 4330 λ 6830Å. This...
Spitzer Infrared Spectrograph Observations of Magellanic Cloud Planetary Nebulae: The Nature of Dust in Low-Metallicity Circumstellar Ejecta
We present 5-40 μm spectroscopy of 41 planetary nebulae (PNe) in the Magellanic Clouds, observed with the Infrared Spectrograph on board the Spitzer Space...
Spitzer IRS spectra of compact Galactic planetary nebulae: The link between dust, evolution, and metallicity
A sample of ~150 compact Galactic PNe has been observed with the Spitzer/IRS spectrograph to characterize their dust properties. These PNe are likely to be at...
Spitzer IRS Spectroscopy of High-Mass Precursors of Planetary Nebulae
We present Spitzer IRS observations of a small sample of heavily obscured IRAS sources displaying both the infrared and OH maser emission characteristic of OH...
Subarcsecond knots and filaments in the molecular hydrogen of the bipolar PN NGC 2346
We present high spatial resolution (~60-90 milliarcseconds) images of the molecular hydrogen emission in the planetary nebula NGC 2346. Molecular hydrogen...
Temperature fluctuations and the chemical composition of planetary nebulae of Type I.
The authors present two new methods to determine the electron temperature based on the He I line intensities. The temperatures derived from these methods are...
The "Príncipes de Asturias" nebula: a new quadrupolar planetary nebula from the IPHAS survey
Context: .The Isaac Newton Telescope Photometric Hα Survey (IPHAS) is currently mapping the Northern Galactic plane reaching to r'=20 mag with typically...
The alpha -element abundances in the most oxygen-poor planetary nebula PNG 135.9+55.9
We present extensive new spectroscopy and imaging of PNG 135.9+55.9. We use these data as constraints to photoionization models to derive limits on the oxygen...