A total of 1-3 per cent of white dwarfs are orbited by planetary dusty debris detectable as infrared emission in excess above the white dwarf flux. In a rare...
-
PublicationThe frequency of gaseous debris discs around white dwarfs
-
PublicationThe High-Excitation Planetary Nebula NGC 246: Optical and Near-Ultraviolet Observations and Two-dimensional Numerical Models
We have imaged the planetary nebula (PN) NGC 246 in the near-ultraviolet wavelengths [Ne V] 342.6 nm, the Bowen fluorescence line of O III at 344.4 nm, and a...
-
PublicationThe ionised and molecular mass of post-common-envelope planetary nebulae. The missing mass problem
Context. Most planetary nebulae (PNe) show beautiful, axisymmetric morphologies despite their progenitor stars being essentially spherical. Close binarity is...
-
PublicationThe mixed chemistry phenomenon in Galactic Bulge PNe
Aims: We investigate the dual-dust chemistry phenomenon in planetary nebulae (PNe) and discuss reasons for its occurrence, by analyzing Spitzer/IRS spectra of a...
-
PublicationThe Nature of Low-Ionization Microstructures in PNe
We discuss here the nature of a rich zoo of knots, filaments, jets and jet-like systems, located--in terms of morphology and kinematics--either inside or...
-
PublicationThe Onset of Photoionization in Post-AGB Stars
During the post-AGB phase the dust shell detaches from the central star and dust temperatures varies between 100 and 200 K. In order to study the onset of photo...
-
PublicationThe outburst and nature of two young eruptive stars in the North America/Pelican Nebula Complex
Context. The sudden optical brightening of two young stellar objects, HBC 722 and VSX J205126.1+440523, located in the North America/Pelican Nebula Complex, was...
-
PublicationThe outburst of the eruptive young star OO Serpentis between 1995 and 2006
Aims:OO Serpentis is a deeply embedded pre-main sequence star in the Serpens NW star-forming region. The star went into outburst in 1995 and gradually faded...
-
PublicationThe post-common envelope central stars of the planetary nebulae Henize 2-155 and Henize 2-161
We present a study of Hen 2-155 and Hen 2-161, two planetary nebulae which bear striking morphological similarities to other planetary nebulae known to host...