
Physics 1997
Stability Analysis of Spherically Symmetric Star in ScalarTensor Theories of GravityDOI: 10.1143/PTP.98.359 Abstract: A stability analysis of a spherically symmetric star in scalartensor theories of gravity is given in terms of the frequencies of quasinormal modes. The scalartensor theories have a scalar field which is related to gravitation. There is an arbitrary function, the socalled coupling function, which determines the strength of the coupling between the gravitational scalar field and matter. Instability is induced by the scalar field for some ranges of the value of the first derivative of the coupling function. This instability leads to significant discrepancies with the results of binarypulsartiming experiments and hence, by the stability analysis, we can exclude the ranges of the first derivative of the coupling function in which the instability sets in. In this article, the constraint on the first derivative of the coupling function from the stability of relativistic stars is found. Analysis in terms of the quasinormal mode frequencies accounts for the parameter dependence of the wave form of the scalar gravitational waves emitted from the OppenheimerSnyder collapse. The spontaneous scalarization is also discussed.
