New anisotropic star solutions in mimetic gravity

Abstract

We extract new classes of anisotropic solutions in the framework of mimetic gravity, by applying the Tolman-Finch-Skea metric and a specific anisotropy not directly depending on it, and by matching smoothly the interior anisotropic solution to the Schwarzschild exterior one. Then, in order to provide a transparent picture we use the data from the 4U 1608-52 pulsar. We study the profile of the energy density, as well as the radial and tangential pressures, and we show that they are all positive and decrease towards the center of the star. Furthermore, we investigate the anisotropy parameter and the anisotropic force, that are both increasing functions of the radius, which implies that the latter is repulsive. Additionally, by examining the radial and tangential equation-ofstate parameters, we show that they are monotonically increasing, not corresponding to exotic matter. Concerning the metric potentials we find that they have no singularity, either at the center of the star or at the boundary. Furthermore, we verify that all energy conditions are satisfied, we show that the radial and tangential sound speed squares are positive and sub-luminal, and we find that the surface redshift satisfies the theoretical requirement. Finally, in order to investigate the stability we apply the Tolman-Oppenheimer-Volkoff equation, we perform the adiabatic index analysis, and we examine the static case, showing that in all cases the star is stable.

Black Holes with Electric and Magnetic Charges in F(R)$F(R)$ Gravity

“…Maybe if we assume another form of F, we will obtain another new black hole which will be different from the black hole given by Equation ( 37) and (50). Moreover, there could be any analytic spherically symmetric interior solution can be derived from the field Equation ( 8) following the procedure done in [113].…”

Extensions of two-field mimetic gravity

“…With appropriate choice of the potential, the generalized model can provide inflation, bounce, dark energy, and so on. This has stimulated extensive cosmological and astrophysical interests [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], and mimetic scenario has also been applied in various modified gravity theories [31][32][33][34][35][36][37][38][39][40][41][42][43][44]. The Hamiltonian analysis of different kinds of mimetic models were investigated in refs.…”

Realistic compact stars in conformal teleparallel gravity

“…Moreover, a non-metricity conformal symmetric teleparallel gravity have been studied in [51]. Also, new anisotropic star solutions in mimetic gravity by imposing the Tolman-Finch-Skea metric have been discussed in [52].…”