Research Of Physics Character For Dark Energy And Dark Energy Star In The Universe

A universe model with matter and dark energy is researched in this thesis, since the complexity of 4-D model, a 2-D toy model is researched firstly, and then we study the real 4-D model, analyze it by using the data of astronomical observation.The dark energy not only affects the evolvement of universe, but also affects the configuration of stars. So some people guess that star may turn into dark energy star after gravitation collapse. A model of dark energy star is also constructed in this thesis, and the relation between temperature and mass are researched. The thesis is organized as follows: In Chap One, the reason of the appearance of dark energy and dark energy star and the main view of this thesis has been introduced. In Chap Two, a 2-D Brans-Dicke cosmological model with the action of strange matter and dark energy is studied, some new cosmological solutions are obtained, which can be used to explain the accelerated expansion of universe; Moreover, the cosmological solutions of 2-D Brans-Dicke string model have been investigated. In Chap Three, a 4-D cosmological model with the action of matter (include dark matter) and dark energy is studied, and the proportion of each element has been estimated according the observation data. In Chap Four, a 2-D dark energy star model with the action of strange matter is studied, equations set of the field and balance equation of star has been deduced, and the influence of temperature on the mass of star has been investigated.The new works of this thesis are as follows: 1. The cosmological solutions of 2-D Brans-Dicke cosmological model in early and late times is researched together, the action of exotic matter and dark energy is analyzed. Moreover, conclusion shows that the universe inflation occurs when the string matter plays a main role and the dual symmetry breaks.2. According to the cosmological solutions of 4-D gravity-scalar field and observation data, the fact that accelerated expansion of universe can be explained, then the proportion of matter (including dark matter) and dark energy can be predicted.3. A 2-D dark energy star model in finite temperature is constructed, equations set of the field and the new balance equation of star has been derived, and the mass of stars is calculated. Moreover, various possible anti-gravitation effects are also predicted.4. In order to ensure the accuracy of result, a matlab program is used to calculate the connection and the curvature.