A relativistic, static and spherically symmetrical stellar model is presented, constituted by a perfect charged fluid. This represents a generalization to the case of a perfect neutral fluid, whose construction is made through the solution to the Einstein-Maxwell equations proposing a form of gravitational potential  $g_{tt}$ and the electric field. The choice of electric field implies that this model supports values of compactness$u=GM/c^2R\leq 0.5337972212$, values higher than the case without electric charge ($u\leq 0.3581350065$), being this feature of relevance to get to represent compact stars. In addition, density and pressure are positive functions, bounded and decreasing monotones, the electric field is a monotonously increasing function as well as satisfying the condition of causality so the model is physically acceptable. In a complementary way, the internal behavior of the hydrostatic functions and their values are obtained taking as a data the corresponding to a star of $1 M_\odot$,for different values of the charge parameter, obtaining an interval for the central density $\rho_c\approx (7.9545,2.7279) 10^{19}$ $ Kg/m^3$ characteristic of compact stars.

We present an exact regular solution of Einstein equations for a static and spherically symmetric spacetime with a matter distribution of isotropic perfect fluid. The construction of the solution is realized assigning a regular potential [Formula: see text] and integrating the isotropic perfect fluid condition for the pressure. The resulting solution is physically acceptable, i.e. the geometry is regular and the hydrostatic variable pressure and density are positive regular monotonic decreasing functions, the speed of the sound is positive and smaller than the speed of the light. An important element of this solution is that its compactness value [Formula: see text] is in the characteristic range of compact stars, which makes a remarkable difference with other models with isotropic perfect fluid, this is [Formula: see text] so that we could represent compact stellar objects as neutron stars. In particular, for the maximum compactness of a star with a mass of [Formula: see text] the radius is [Formula: see text] and their central density [Formula: see text] is characteristic of compact stars.

A model for low mass compact objects with compactness ratio $u\leq 0.06092997016$ is presented here. Density, pressure and sound speed are regular and monotonic decreasing functions. The change between the central density $\rho_c$ and the density on the surface $\rho_b$ is lower than $3.94\%$ and the maximum change occurs for the biggest compactness, i.e. $\rho_c=1.039350237\rho_b$. This allows us to apply this model for the case of compact stars in which the density variation is very small. In particular, we can use this model for PSR B0943 + 10, a quark star candidate, with radius $R=2.6{\rm Km}$ and mass $M=0.2 M_\odot$. According to our model it comes out that the density on the surface is $\rho_b=5.388074 \times 10^{17} Kg/m^3$ and its central density $\rho_c=1.007150 \rho_b$ is slightly bigger than the surface density and larger than the nuclear density.

A stellar model with an electrically charged anisotropic fluid as a source of matter is presented. The radial pressure is described by a Chaplygin state equation, [Formula: see text], while the anisotropy [Formula: see text] is annulled in the center of the star [Formula: see text] is regular and [Formula: see text], the electric field, is also annulled in the center. The density pressures and the tangential speed of sound are regular, while the radial speed of sound is monotonically increasing. The model is physically acceptable and meets the stability criteria of Harrison–Zeldovich–Novikov and in respect of the cracking concept the solution is unstable in the region of the center and potentially stable near the surface. A graphic description is presented for the case of an object with a compactness rate [Formula: see text], mass [Formula: see text] and radius [Formula: see text] km that matches the star Vela X-1. Also, the interval of the central density [Formula: see text], which is consistent with the expected magnitudes for this type of stars, which shows that the behavior is accurate for describing compact objects.

A static and spherically symmetric stellar model is described by a perfect charged fluid. Its construction is done using the solution of the Einstein–Maxwell equations for which we specify the temporal metric and the electric field which is a monotonic increasing function null in the center. The density, pressure and speed of sound turn out to be regular functions, positive and monotonic decreasing as function of the radial distance. Also, the speed of sound is lower than the speed of light, that is to say, it does not violate the condition of causality. The value of compactness [Formula: see text], so the model is useful to represent neutron stars of quark stars. In a complementary manner, we report the physical values when describing a star of mass [Formula: see text] and radius [Formula: see text], in such case [Formula: see text], and given the presence of the charge, the interval for the central density [Formula: see text].