Strange stars in Krori-Barua space-time under f(R; T) gravity (1803.00442v2)

Abstract: In the present work, we study about highly dense compact stars which are made of quarks, specially strange quarks, adopting the Krori-Barua (KB)~\cite{Krori1975} metric in the framework of $f(R,T)$ gravity. The equation of state (EOS) of a strange star can be represented by the MIT bag model as $p_r(r)=\frac{1}{3}[\rho(r)-4B_g]$ where $B_g$ is the bag constant, arises due to the quark pressure. Main motive behind our study is to find out singularity free and physically acceptable solutions for different features of strange stars. Here we also investigate the effect of alternative gravity in the formation of strange stars. We find that our model is consistent with various energy conditions and also satisfies Herrera's cracking condition, TOV equation, static stability criteria of Harrison-Zel$'$dovich-Novikov etc. The value of the adiabatic indices as well as the EOS parameters re-establish the acceptability of our model. Here in detail we have studied specifically three different strange star candidates, viz. $PSRJ~1614~2230, Vela~X-1$ and $Cen~X-3$. As a whole, present model fulfils all the criteria for stability. Another fascinating point we have discussed is the value of the bag constant which lies in the range $(40-45)$~MeV/fm$^{3}$. This is quite smaller than the predicted range, i.e., $(55-75)$~MeV/fm$^{3}$ ~\cite{Farhi1984,Alcock1986}. The presence of the constant ($\chi$), arises due to the coupling between matter and geometry, is responsible behind this reduction in $B_g$ value. For $\chi=0$, we get the higher value for $B_g$ as the above mentioned predicted range.