Compact stars described by a charged model

Abstract

A charged stellar model is presented by constructing a solution to the Einstein–Maxwell equations system in a spherically symmetrical static time-space. The rate of compactness for the model depends on two parameters [Formula: see text], one of them [Formula: see text] associated to the charge, which allows a value of compactness [Formula: see text] higher than the neutral case. The density and pressure are regular functions, positive and monotonically decreasing and the function of charge is positive regular and monotonically increasing, its shown that the model satisfies the condition of causality, the geometry is regular and as such the model is physically acceptable. Although the model can be applicable for a variety of stars, considering a star with mass [Formula: see text] for [Formula: see text] the range of compactness is [Formula: see text] and radius [Formula: see text], in this case the range of values for the central density is [Formula: see text] greater than the value of the nuclear density and consistent with that expected for stars with this compactness rate.

An interior solution with perfect fluid

“…On the other hand, the stability of the solutions is guaranteed due to the fact that their adiabatic index is a monotonic increasing function with a minimum value γ ≥ 14.615. This exact internal solution can be generalized to the charged or anisotropic case that is able to represent stars with similar characteristics to the ones presented here, with the advantage that the interval of the compactness rate will be greater than in the case of the perfect fluid,[35][36][37] like other solutions with perfect fluid have been generalized [38][39][40][41][42]. Another relevant point is that the solution may be used as2050141-13 Mod.…”

Determination of the charge for strange stars

“…guarantees the absence of event horizons. In addition of this the functions (9) that describe the geometry were initially proposed to model anisotropic chargeless and charged perfect fluid objects [74], afterwards they were employed for the case of a charged anisotropic fluid with a state equation type Chaplygin [76] and with quintessence sources of matter [77], as well as for a linear equation of state [78] and non linear equation of state [79].…”

“…It is also applicable in alternative gravitational theory models [80,81]. This same geometry allows for the description of models that are differentiated for the type of sources of matter in situations with or without equation of state [74,[76][77][78][79][80][81]. The different models proposed were applied to describe the interior of many stellar objects for which their observational data is known and also it has been shown that the geometry is regular and absent of event horizon, motivated by this, in this report the focus will be centered in the construction of a model, the description of it's behaviour and it's application to determining the possible values of the charge considering some values of the Bag constant inside of the admissible interval of it.…”

A charged star with geometric Karmarkar condition

“…The anisotropy in relation to compact objects has been addressed in the analysis of stars with ordinary matter for an incompressible fluid [6] and with non-constant density [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], in the analysis of bosonic stars [22], in the context of Brans-Dicke gravity [23], in alternative gravitation theories like the f (T) [24], in the consideration of stars with quintessence type matter [25][26][27][28][29] and also in the analysis of hypothetical objects such as gravastars [30]. In the charged case we have models that consider a perfect charged fluid [31][32][33][34][35][36][37] as well as in the case of objects with charged anisotropic fluid [38][39][40][41][42][43][44][45][46]. From a theoretical point of view, the anisotropy may occur for different motives: when the density of the matter is superior to 10 15 g/cm 3 Δ ≠ 0 as a result that at these orders the interactions are relativistic [47]; phase transitions of the matter, when changing to a su...…”