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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 81 to 90 of 1016 (0.013 seconds)| 81 |
On the origin of planetsCoates, I. E. January 1980 (has links)
The criteria to be satisfied by a successful theory of the origin of the solar system are discussed before highlighting the difficulties of early two-body interaction theories. It is shown that these do not apply to Woolfson's capture theory which proposes that a light' diffuse protostar was tidally disrupted during a close encounter with the Sun and that the captured material might condense to form massive protoplanets. The smoothed particle hydrodynamic technique of Gingold & Monaghan is improved to provide a model for the computer simulation of stellar encounters. The protostar is replaced by a number of randomly distributed fluid elements, from which a density distribution may be recovered by a statistical technique. This distribution leads to a gravitational field and with a suitable thermodynamic model the pressure is determined at any point, enabling the dynamical evolution of the protostar to be simulated. The model is tested on a number of hydrostatic and hydrodynamic problems. A collapsing protostar is seen to be tidally disrupted during a close stellar encounter and the captured material moves quickly away from the Sun. This provides the optimal conditions for protoplanetary condensation. The effect of an initial protostellar rotation is also considered. It is shown that the quantity of material captured is critically dependent on the alignment of the protostellar spin axis to the orbital plane and, in an extreme case, might prevent the disruption of the protoster. The behaviour of a contracting protoplanet in the solar tidal field is investigated. It is shown that, despite severe distortion, it may well survive a perihelion passage without disruption and after further contraction may regain its spheroidal shape. Finally, a number of extensions to the capture theory are suggested.
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The gaseous environment of quasarsBremer, Malcolm Neal January 1993 (has links)
No description available.
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| 83 |
Aperture synthesis observations of the Sunyaev-Zel'dovich effectJones, Michael Edward January 1990 (has links)
No description available.
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| 84 |
Studies in out-flowing material in star-forming regionsRussell, Adrian Paul Grenville January 1987 (has links)
No description available.
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| 85 |
Some aspects of particle creation from charged black holesLohiya, D. January 1982 (has links)
No description available.
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| 86 |
Very long baseline interferometry at 81.5 MHzHartas, J. S. January 1983 (has links)
No description available.
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| 87 |
Cosmological evolution at edges of the radio source populationDingley, Stephen John January 1990 (has links)
No description available.
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| 88 |
Seismological traits of the sun's interior structureEllis, Anthony Nicholas January 1988 (has links)
No description available.
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| 89 |
Observations and models of molecular cloudsMartin, H. M. January 1983 (has links)
No description available.
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| 90 |
The rich star clusters in the Large Magellanic CloudElson, R. A. W. January 1986 (has links)
No description available.
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