16,592 research outputs found

    All spherically symmetric charged anisotropic solutions for compact star

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    In the present paper we develop an algorithm for all spherically symmetric anisotropic charged fluid distribution. Considering a new source function ν(r)\nu(r) we find out a set of solutions which is physically well behaved and represent compact stellar models. A detailed study specifically shows that the models actually correspond to strange stars in terms of their mass and radius. In this connection we investigate about several physical properties like energy conditions, stability, mass-radius ratio, electric charge content, anisotropic nature and surface redshift through graphical plots and mathematical calculations. All the features from these studies are in excellent agreement with the already available evidences in theory as well as observations.Comment: 28 pages, 15 figures, major changes in the text. arXiv admin note: text overlap with arXiv:1408.5126 by other author

    Anisotropic models for compact stars

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    In the present paper we obtain an anisotropic analogue of Durgapal-Fuloria (1985) perfect fluid solution. The methodology consists of contraction of anisotropic factor Δ\Delta by the help of both metric potentials eνe^{\nu} and eλe^{\lambda}. Here we consider eλe^{\lambda} same as Durgapal-Fuloria (1985) whereas eνe^{\nu} is that given by Lake (2003). The field equations are solved by the change of dependent variable method. The solutions set mathematically thus obtained are compared with the physical properties of some of the compact stars, strange star as well as white dwarf. It is observed that all the expected physical features are available related to stellar fluid distribution which clearly indicate validity of the model.Comment: 18 pages, 13 figures, 4 tables; Published in European Physical Journal

    Generalized model for anisotropic compact stars

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    In the present investigation an exact generalized model for anisotropic compact stars of embedding class one is sought for under general relativistic background. The generic solutions are verified by exploring different physical aspects, viz. energy conditions, mass-radius relation, stability of the models, in connection to their validity. It is observed that the model present here for compact stars is compatible with all these physical tests and thus physically acceptable as far as the compact star candidates RXJ 185637RXJ~1856-37, SAX J 1808.43658 (SS1)SAX~J~1808.4-3658~(SS1) and SAX J 1808.43658 (SS2)SAX~J~1808.4-3658~(SS2) are concerned.Comment: 19 pages, 12 figures, 3 table

    A new model for spherically symmetric anisotropic compact star

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    In this article we obtain a new anisotropic solution for Einstein's field equation of embedding class one metric. The solution is representing the realistic objects such as Her X1Her~X-1 and RXJ 185637RXJ~1856-37. We perform detailed investigation of both objects by solving numerically the Einstein field equations under with anisotropic pressure. The physical features of the parameters depend on the anisotropic factor i.e. if anisotropy is zero everywhere inside the star then the density and pressures will become zero and metric turns out to be flat. We report our results and compare with the above mentioned two compact objects on a number of key aspects: the central density, the surface density onset and the critical scaling behavior, the effective mass and radius ratio, the anisotropization with isotropic initial conditions, adiabatic index and red shift. Along with this we have also made a comparison between the classical limit and theoretical model treatment of the compact objects. Finally we discuss the implications of our findings for the stability condition in relativistic compact star.Comment: 13 pages, 9 figures, 2 table

    Market Integration, Soccer, and the EU: Changes in the Game’s Core Territories

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    This paper uses soccer as a lens to look at governance structures and how they affect labor markets and economic outcomes in major European countries. It looks at three different models of soccer governance: “coordinated,” “liberal,” and “neutral,” found in the five major European soccer leagues (England, Germany, Spain, Italy, and France) and suggests that coordinated structures may have a comparative advantage over liberal structures
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