Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"Novae"”.
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Extragalactic Novae and Their Progenitors
Novae are binary systems containing a white dwarf (WD) and a less-evolved companion star, either a main-sequence, sub-giant or red giant star. The WD accretes matter from the companion through Roche lobe overflow or via a stellar wind. As material is accreted, the pressure and temperature at the …
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Multiband Observations of Recurrent Novae
Recurrent novae are binary systems which undergo outbursts due to a thermonuclear runaway on a timescale of decades. Two systems, U Scorpii and RS Ophiuchi, are the main focus of this thesis having gone into outburst in 2010 and 2006 respectively. Optical and near-IR spectroscopy of U Sco obtained …
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Multiwavelength studies of classical novae
Classical novae are transient astronomical events resulting from an eruption on the surface of an accreting white dwarf in interacting binary stars, namely cataclysmic variables. These eruptions and their progenitors are ideal astronomical events/objects to study a variety of interesting topics, …
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The outbursts and environments of novae
Classical and Recurrent novae (CNe/RNe) are interacting close binary systems in which mass is transferred from a donor star to the surface of an accreting compact companion resulting in an outburst. Their study is important for our understanding of several branches of modern day astrophysics. The …
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Radiation hydrodynamic processes in the lightcurve evolution of classical novae
… radiation hydrodynamic description of classical novae with HYDRA, a 1-D, Lagrangian hydrodynamics code developed specifically for this project. After reviewing the architecture and performance of HYDRA, we proceed to apply it to three different problems of classical nova evolution. The first of …
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Investigation of the Progenitors and Outbursts of Classical and Recurrent Novae
Classical novae (CNe) are interacting binary systems whose outbursts are powered by a thermonuclear runaway in accreted material on the surface of a white dwarf (WD). The secondary stars in such systems fill their Roche lobe and material is transferred onto the WD primary star via an accretion …
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Characterization of Mycochemicals and Bioactivities of a New Zealand Native Mushroom Hericium novae-zealandiae
… native edible mushroom now known as Hericium novae-zealandiae. There is little to no published scientific data available on this mushroom. The aim of this study was to investigate the chemical constituents in H. novaezealandiae and their biological activities. Normal column chromatography …
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Radio observations as a tool to study shock interactions and mass ejections in novae
… thesis presents radio frequency studies of three novae, namely V445 Puppis, V3890 Sagitarii and V339 Delphini. The new data, in this thesis, represent some of the most detailed and comprehensive radio light curves to date. In these systems a thermonuclear eruption occurs on the surface a white …
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Exploring the application of new telescope technologies in the testing of dwarf novae accretion models
In this thesis I investigate emerging telescope technologies and demonstrate, within the context of accretion in cataclysmic variables (CVs), their role in contributing to the stellar variability studies which help drive their development.
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On the model for U Geminorum
… comprises several types of variable star - novae, recurrent novae, dwarf novae; and to these we add the nova-like variables, stars which exhibit many of the characteristics of the novae but which have not been observed to erupt. U Geminorum, discovered by Hinds in 1855, is the nomotype of …
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Magnetohydrodynamical phenomena in gaseous disks
… the cataclysmic variables (CVs). These include novae, dwarf novae and nova-like variables. Disks are maintained by mass transferred from a Roche-lobe filling secondary star to a white dwarf. More information can be found in Warner (1976) and Robinson (1976). As is pointed out in the final …
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Atomic processes in nova shells
… luminosity phase traced. The properties of neon novae are summarized and compared with the features seen in the optical spectra of old classical novae. Enhanced neon abundances are used in the model of the CP Pup Shell to investigate its effect on the evolution of the shell. Finally, the results …
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Eclipsing Cataclysmic Variables With TESS
… spanning multiple subclasses: nova-likes, dwarf novae, classical novae, and intermediate polars. Eclipsing systems are crucial for probing disk structure and evolution, as their geometry permits direct observation of temporal variations. The continuous coverage provided by TESS enables detailed …
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The role of phytotechnology in the rehabilitation of the BHPBilliton Cannington Ag-Pb-Zn mine
… plant species (Chloris gayana, Crotalaria novae-hollandiae, Cymbopogon ambiguus, Cymbopogon bombycinus, Cyperus victoriensis, Gomphrena canescens and Triodia molesta) were cultivated in soil contaminated with mine tailings (60 micrograms Ag g ⁻', 2039 micrograms As g ⁻', 30 micrograms Cd g …
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Shear instabilities between accretion disks and nova objects
Classical novae are thermonuclear explosions on the surface of white dwarfs caused by accretion from a companion star. Most studies focus on modelling the explosive phase (thermonuclear runaway), while this thesis, instead, focuses on the pre-explosion stage, investigating how shear instabilities …
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The evolution of isotoipc abundances from high-redshift to the local universe
… in this thesis: first, to test the claim that novae are required, in order to explain the carbon isotope patterns in the Milky Way (Romano & Matteucci 2003); second, to test the claim that sulphur isotope patterns at high-redshift require an initial mass function biased towards massive stars …
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Superhumps in AM Canum Venaticorum stars
… that produces superhumps in SU UMa dwarf novae. Superhumps are optical variations observed during the superoutbursts of SU UMa stars with periods a few percent in excess of the orbital period. The superhumps usually disappear as the star declines to quiescence after a superoutburst. …
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Plant Species and Soil Type Effects on Root Characteristics, Microbiota and Plant-soil Feedback Responses in Four Prairie Species
… Aster laevis, Parthenium integrifolium, Aster novae-angliae and Andropogon gerardii were grown in sterilized control soil and soil collected from beneath monocultures of A. laevis, P. integrifolium, and A. gerardii. Soil type (heterospecific and conspecific sources) was expected to have the …
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Determining the jet opening-angle of gamma-ray bursts
… rapidly rotating massive stars - dubbed "hyper-novae." In 1987, a supernova (SN 1987A) was detected in the Large Magellanic Cloud - its progenitor was a blue, rapidly rotating supergiant that was probably a member of a binary system that underwent merger prior to the supernova event [1]. Was SN …
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