Please use this identifier to cite or link to this item:
http://hdl.handle.net/11375/21352
Title: | Stellar Structure in Scalar-Tensor Gravity |
Authors: | Horbatsch, Michael |
Advisor: | Burgess, Cliff |
Department: | Physics and Astronomy |
Keywords: | stellar structure, scalar-tensor, gravity, Newtonian polytropes, mass, radius, density |
Publication Date: | Oct-2008 |
Abstract: | Stellar structure is investigated within the framework of scalar-tensor gravity. Novel perturbative analytical results are obtained for constant-density stars and for Newtonian polytropes in the quadratic model with coupling function A(Φ) = exp(αΦ+1/2βΦ^2). They are compared to full numerical calculations, and possible applications to main-sequence stars, white dwarfs, and the Chandrasekhar mass are indicated. It is found that Buchdahl's theorem is violated in Brans-Dicke theory for stars with exponentially-decaying density profiles. However, the mass-to-radius ratio M/R tends to the constant-density value in a certain limit. It is observed that for β < 0, there exists a maximum value of η = P0/ρo for constant-density stars, where P0 and ρ0 are the central pressure and density, respectively. It is conjectured that if such a maximum value also exists for other equations of state, and is less than the constant-density maximum value, then knowledge of P/ρ in the centre of a star can be used to constrain β. |
URI: | http://hdl.handle.net/11375/21352 |
Appears in Collections: | Digitized Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Horbatsch_Michael_2008Oct_Masters..pdf | 4.22 MB | Adobe PDF | View/Open |
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