Related papers: The planetary nebula IC 4776 and its post-common-e…
The formation of Wolf-Rayet central stars of planetary nebulae ([WR] CSPNe) whose spectroscopic appearance mimics massive WR stars remains poorly understood. Least understood is the nature and frequency of binary companions to [WR] CSPNe…
We present [N II] and H-alpha images and high resolution long-slit spectra of the planetary nebula IC 4846, which reveal, for the first time, its complex structure and the existence of collimated outflows. The object consists of a…
A number of planetary nebulae show binary central stars and significant abundance discrepancies between values estimated from colisionally excited lines when compared to the same abundances estimated from recombination lines. One approach…
A current issue in the study of planetary nebulae with close binary central stars is the extent to which the binaries affect the shaping of the nebulae. Recent studies have begun to show a high coincidence rate between nebulae with…
Close binary central stars of planetary nebulae (PNe) must have formed through a common envelope evolution during the giant phase experienced by one of the stars. Transfer of the angular momentum from the binary system to the envelope leads…
We present a detailed study of the barium star at the heart of the planetary nebula Abell 70. Time-series photometry obtained over a period of more than ten years demonstrates that the barium-contaminated companion is a rapid rotator with…
Binary central stars have long been invoked to explain the vexing shapes of planetary nebulae (PNe) despite there being scant direct evidence to support this hypothesis. Modern large-scale surveys and improved observing strategies have…
Abell 70 (PN G038.1-25.4, hereafter A 70) is a planetary nebula (PN) known for its diamond ring appearance due a superposition with a background galaxy. The previously unstudied central star is found to be a binary consisting of a G8IV-V…
I present the results of time-resolved photometry of a selection of central stars of planetary nebulae. The study reveals periodic variability in two of the eight central stars observed, those of NGC 6026 and NGC 6337. The variability…
We report on the serendipitous discovery of the first central star of a planetary nebula (PN) that mimics the helium- and nitrogen-rich WN sequence of massive Wolf-Rayet (WR) stars. The central star of IC 4663 (PN G346.2-08.2) is dominated…
Binarity has been hypothesised to play an important, if not ubiquitous, role in the formation of planetary nebulae (PNe). Yet there remains a severe paucity of known binary central stars required to test the binary hypothesis and to place…
The planetary nebula SuWt 2 (PN G311.0+02.4), is an unusual object with a prominent, inclined central emission ellipse and faint bipolar extensions. It has two A-type stars in a proven binary system at the centre. However, the radiation…
In an attempt to determine how many planetary nebulae derive from binary interactions, we have started a project to measure their unbiased binary fraction. This number, when compared to the binary fraction of the presumed parent population…
The rate of stellar evolution can rarely be measured in real time. The fastest evolution (excluding event-driven evolution), where stars may evolve measurably over decades, is during the post-AGB phase. In this paper we provide direct…
It is widely believed that central star binarity plays an important role in the formation and evolution of aspherical planetary nebulae, however observational support for this hypothesis is lacking. Here, we present the most recent results…
The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary…
The central star of the planetary nebula PRTM 1 (PN G243.8-37.1) was previously found to be variable by M. Pena and colleagues. As part of a larger programme aimed towards finding post common-envelope binary central stars we have monitored…
It is now clear that a binary evolutionary pathway is responsible for a significant fraction of all planetary nebulae, with some authors even going so far as to claim that binarity may be a near requirement for the formation of an…
A number of efforts are underway to detect close binary stars in planetary nebulae. The primary goal of these studies is to determine the binary fraction of central stars. The next stage is a detailed analysis of the binaries to determine…
Six planetary nebulae (PN) are known in the Kepler space telescope field of view, three newly identified. Of the 5 central stars of PN with useful Kepler data, one, J193110888+4324577, is a short-period, post common envelope binary…