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 10 of 10 for “"White dwarf stars"”.
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The gravity oscillations of white dwarf stars
… numerical investigation of the oscillations of white dwarfs which is discussed below was begun at the suggestion of Professor Warner soon after the discovery of periodic variations in several cataclysmic variables. Its completion within a reasonable time was greatly helped by the availability of …
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Spectroscopy of white dwarf stars observed by HETDEX.
Approximately 97% of all stars will become white dwarf stars at the end of their life cycles, making them excellent benchmarks for testing theories of stellar evolution. For the purposes of numerical modelling, they can be treated as simple objects composed of two structures that can be treated …
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Polluted White Dwarfs: Insights into Ancient Extrasolar Planetary Systems
… this thesis, I demonstrate how the pollution of white dwarf stars by rocky exoplanetary material offers an insight into the bulk composition of rocky exo-planets, and thus, the geological processes which occur on them. I present a model which reproduces the atmospheric metal abundances present in …
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Pulsations in the white dwarf primary of a cataclysmic variable star
… powerful techniques for the study of pulsating white dwarf stars. If these techniques could be applied to the white dwarf primaries of Cataclysmic Variable stars, the study of accretion in interacting binary systems would benefit enormously. Our understanding of normal modes in white dwarf …
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Population boundaries and gravitational-wave templates for evolving white dwarf binaries
We present results from our analysis of double white dwarf (DWD) binary star systems in the inspiraling and mass-transfer stages of their evolution. Theoretical constraints on the properties of the white dwarf stars allow us to map out the DWD trajectories in the gravitational-wave …
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Cool white dwarfs and the age of the galaxy
White dwarf stars represent the most common endpoint of stellar evolution and therefore provide a reliable estimate of the star formation history and age of different Galactic populations. The major observational requirement for accurate age measurements is to have a large sample of cool, old white …
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Accretion topics in astrophysics
… The third work studies the tidal stripping of a white dwarf spiraling into a massive black hole. The stripped matter accretes onto the black hole producing a transient emission, presumably periodic, observable with X-ray and optical telescopes. At the same time the white dwarf emits gravitational …
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Observational Insights into White Dwarf Planetary Systems
… their characterisation. Spectroscopic studies of white dwarfs ‘polluted’ by planetary material are a unique laboratory allowing measurements of their bulk composition. This thesis focuses on these polluted white dwarfs to observationally investigate how the material ultimately accretes onto the …
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Exogeology as Revealed by Polluted White Dwarfs
… source of information in the form of dead stars called white dwarfs. Many white dwarfs have accreted remnants of their own planetary systems, causing their atmospheres to become polluted by heavy elements. The relative quantities of these elements contain a wealth of information about the …
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Strong Magnetic Field Effects and Molecular Processes with Applications to White Dwarfs
… fields of strength applicable to magnetic white dwarfs, i.e. B < 10<sup>3</sup> megagauss, have been investigated for field-free principal quantum numbers n < 6. Finite proton mass corrections are included. Relativistic corrections are also investigated. Transition probabilities are …