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In this work, we present an exact interior solution to a physically acceptable Einstein–Maxwell equation system, assuming a static and spherically symmetric spacetime with a distribution of matter from a perfect charged fluid to represent a generalization of a model for a perfect chargeless fluid. The charge parameter modifies the mass function, its compactness rate and the comportment of the speed of sound. The behavior analysis of the functions of density, pressure and charge shows that the solution is applicable for the description of relativistic compact stars. In particular, we analyze the behavior of these functions for the values of observed mass $M\in [0.95,1.13]M_{\odot }$ and the theoretical radius interval estimated previously $R\in [8.101,8.501]$km from the star LMC X-4. Thus, the biggest charge value of maximum charge $Q=1.73\times 10^{20}$C occurs for the maximum compactness $u=0.2059$.

A new interior solution of Einstein’s equations is derived for a static and spherically symmetric space–time that contains fluid with anisotropic pressures, characterized by a parameter N. The model presented is a generalization to a proposal which contemplated a perfect fluid, which allows us to do an analysis of the impact of the anisotropy on the compactness, density and speed of sound. Taking the observational data of the mass $M=1.7M_{\odot }$ and radius $R=9$ km as well as the mass $M=1.4M_{\odot }$ and radius $R=11$km reported for the star EXO 1745-248, it is determined that the range of values of the density varies between $5.7651\times 10^{17}$ and $1.0937\times 10^{18}$ and these increase as the anisotropy parameter increases; it also shows an effect of the anisotropy on the speed of sound. The stability of the solution is shown through the Zeldovich criteria and through the adiabatic index, and from a graphic analysis it is verified that the behavior of the density, pressures and speed of sound are physically acceptable.