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Stellar Structure in Scalar-Tensor Gravity

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. / Thesis / Master of Science (MSc)

Identiferoai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/21352
Date10 1900
CreatorsHorbatsch, Michael
ContributorsBurgess, Cliff, Physics and Astronomy
Source SetsMcMaster University
Languageen_US
Detected LanguageEnglish
TypeThesis

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