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 626 for “"Stellar"”.
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On the complex stellar populations of ancient stellar systems
The study of ancient stellar systems in the vicinity of the Milky Way provides a wealth of information on the conditions, in the early Universe, that led to the properties we observe today in galaxies and in their constituent components. Resolved stellar populations enable us to gain detailed …
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Constraining the Origin of Multiple Stellar Populations in Stellar Clusters
… These abundance variations (or multiple stellar populations) are ubiquitous to all globular clusters studied to date. The pursuit to explain this longstanding prob- lem using these new constraints (i.e. the abundance variations), has reinvigorated the study of globular clusters, and at …
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Stellar Energy Feedback in Superbubbles
… X-ray emission from the superbubble in M17. The stellar population in M17 is young, only 1 million years old, suggesting no supernovae have occurred and providing a rare opportunity to test the predictions of wind-blown bubble models on superbubble scales without confusion from supernovae. The …
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Adaptive Optics for Stellar Interferometry
The limitations of current stellar interferometers is their low sensitivity, and the next generation will account for this by using larger apertures. The phase aberrations from seeing will need the consideration of adaptive optics (AO). Accordingly, this dissertation will first examine the problem …
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Binary evolution in stellar dynamics
Computational studies of the classical gravitational N-body problem have demonstrated the importance in bound systems of energetic binaries formed dynamically. Since analytic and some numerical studies generally neglect three-body interactions, by which these form, it is desirable to establish what …
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Magnetic fields and stellar oscillations
… With sufficiently precise photometry, stellar oscillations can be detected through the periodic variations they induce in a star's brightness. Understanding the connection between the internal structure of a star and the properties of its normal modes is the focus of stellar oscillation …
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Modelling interstellar extinction in stellar populations
In stellar astrophysics, the determination of the magnitude of interstellar extinction is critical, due to its effect on the observed brightness and colour of the stars. Extinction is therefore an important factor in deriving scientific information from the colour-magnitude diagrams (CMDs) of …
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Reconstruction of stellar images from correlations
The problem of object reconstruction from a series of short-exposure astronomical image data observed by ground-based telescopes is addressed. The observations are seriously degraded by atmospheric turbulence as well as corrupted by photon noise, detection noise and background noise. An approach …
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Stellar interferometry - detectors and the atmosphere.
… Telescope (COAST) project. COAST is a novel stellar interferometer under construction in Cambridge, designed to obtain stellar images with an angular resolution equivalent to that of a 100m telescope. The success of this design requires innovation in a number of areas including photo-detector …
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Higher-order processes in stellar opacities
Made available in DSpace on 2011-05-07T12:30:15Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9702493.pdf: 2570929 bytes, checksum: 5033c0bfef533098363e28741dcf7ac0 (MD5) Previous issue date: 1996
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Stellar occultation investigations of Pluto's atmosphere
We investigate the shape of Pluto's atmosphere using data from the occultation of the V=15.7 star P131.1 by Pluto on 2002 Aug 21 (UT). We find that Pluto's atmosphere, as projected onto the sky, is noticeably non-circular. This implies an overall ellipsoidal shape, which could be an indication of …
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Stellar occultation studies of Triton's atmosphere
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996.
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Laser metrology system for stellar interferometry
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.
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Chemical composition study of Galactic stellar substructures /
… conclusion that the origin of the GCS kinematic stellar groups was different from Galactic streams which originated in a course of the resonant interactions between stars in the outer disk and the Galactic bar. We revisited the determination for one of GCS kinematic group stars. The chemical …
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Dense stellar systems and massive black holes
… MBH are the fact that (a) compact stars and stellar-mass black holes can gradually inspiral into the SMBH due to the emission of gravitational radiation, which is known as an “Extreme Mass Ratio Inspiral” (EMRI), and (b) stars can produce gases which will be accreted by the SMBH through …
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Galactic Stellar Haloes in the CDM Model
This thesis studies galactic stellar haloes built up through the tidal disruption of accreted dwarf galaxies. Numerical simulations are used to explore this process in the context of the Cold Dark Matter model of cosmological structure formation. We predict the properties of stellar structures that …
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Metallicities and stellar populations in spiral bulges
… line-strengths comparable with those of single stellar populations of approximately solar metallicity or above. In bulges, central line-strengths are shown to lie close to, or within, the loci defining solar abundance ratio SSPs. The large number (24) of indices measured in this study, in …
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