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Article
The double-degenerate, super-Chandrasekhar nucleus of the planetary nebula Henize 2-428
The probable evolution of the planetary nebula Henize 2-428 is examined, from a close binary system in which both stars ejected their envelopes to the white dwarf stage with a short orbital period and combined...
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Chapter and Conference Paper
Local Group Census: The Dwarf Irregular Galaxy NGC6822
In the framework of the Local Group Census (LGC), an imaging programme to search for emission line objects in the Local Group, we present the detection of 13 new candidate planetary nebulae (PNe) and follow-up...
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Chapter and Conference Paper
Local Group Census: The Dwarf Irregular Galaxy NGC6822
In the framework of the Local Group Census (LGC), an imaging programme to search for emission line objects in the Local Group, we present the detection of 13 new candidate planetary nebulae (PNe) and follow-up...
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Article
An energetic stellar outburst accompanied by circumstellar light echoes
Some classes of stars, including novae and supernovae, undergo explosive outbursts that eject stellar material into space. In 2002, the previously unknown variable star V838 Monocerotis brightened suddenly by ...
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Chapter
Are Microstructures in the Outer Shells of PNe Fossil Condensations of the AGB Wind?
Some planetary nebulae (PNe) show microstructures of low ionization located in their outer regions, i.e. external to the bright rim defined by the fast vs. slow wind interaction region. Morphological and kinem...
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Chapter and Conference Paper
Multiwavelength Kinematics of the PNe Humason 1–2 and NGC 7662
The conventional interpretation of the “Wilson effect”is based on the fact that, in a simple photoionization model of a thick shell in free expansion, the elements with a high ionization potential are found in...
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Chapter and Conference Paper
New Radiative Transfer Models of Disc Galaxies and the Scale-Length Test for Dust Diagnostics
We present a set of face–on models of the radiative transfer (RT) of stellar light in exponential discs, taking into account absorption and multiple scattering (diffusion) by dust. At any point in the exponential...
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Chapter and Conference Paper
Morphology and Evolution of Planetary Nebulae
A large set of narrow-band images of planetary nebulae (PNe) have been studied together with the location of their nuclei (PNNi) on the logT eff — logL/L ⊙ plane, in order to discl...
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Chapter and Conference Paper
High Velocity Bipolar Outflows in Planetary Nebulae: NGC 6537 and Hb 5
Bipolar symmetry characterizes the morphology of a large number of objects thought to be protoplahetary nebulae. Among these, NGC 6537 and Hb 5 were observed on July 1991 at the 3.5m NTT telescope of the European...
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Chapter and Conference Paper
Cigale Observations of NGC 3198
Scanning Perot-Fabry observations (data-cubes of contiguous sub-ångstrom monochromatic images) allow us to isolate line-emission from nearby continuum using a ‘local’ very narrow-band filter, without being tro...
