科研之友
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摘要
We study strange stars in the framework of f (R,T) theory of gravity. To provide exact solutions of the field equations it is considered that the gravitational Lagrangian can be expressed as the linear function of the Ricci scalar R and the trace of the stress-energy tensor T, i.e. f (R,T) = R + 2 chi T, where chi is a constant. We also consider that the strange quark matter (SQM) distribution inside the stellar system is governed by the phenomenological MIT bag model equation of state (EOS), given as p(r) = 1/3 (rho - 4B), where B is the bag constant. Further, for a specific value of B and observed values of mass of the strange star candidates we obtain the exact solution of the modified Tolman-Oppenheimer-Volkoff (TOV) equation in the framework of f (R,T) gravity and have studied in detail the dependence of the different physical parameters, like the metric potentials, energy density, radial and tangential pressures and anisotropy etc., due to the chosen different values of chi. Likewise in GR, as have been shown in our previous work [Deb et al., Ann. Phys. (Amsterdam) 387, 239 (2017)] in the present work also we find maximum anisotropy at the surface which seems an inherent property of the strange stars in modified f (R,T) theory of gravity. To check the physical acceptability and stability of the stellar system based on the obtained solutions we have performed different physical tests, viz., the energy conditions, Herrera cracking concept, adiabatic index etc. In this work, we also have explained the effects, those are arising due to the interaction between the matter and the curvature terms in f (R,T) gravity, on the anisotropic compact stellar system. It is interesting to note that as the values of chi increase the strange stars become more massive and their radius increase gradually so that eventually they gradually turn into less dense compact objects. The present study reveals that the modified f (R,T) gravity is a suitable theory to explain massive stellar systems like recent magnetars, massive pulsars and super-Chandrasekhar stars, which cannot be explained in the framework of GR. However, for chi = 0 the standard results of Einsteinian gravity are retrieved.
- 出版日期2018-4-16
