@article {
author = {Ghaffarnejad, Hossein and Naderi, Leyla},
title = {Modified Gauge Invariant Einstein-Maxwell Gravity and Stability of Spherical Perfect Fluid Stars with Magnetic Monopoles},
journal = {Iranian Journal of Astronomy and Astrophysics},
volume = {10},
number = {4},
pages = {365-383},
year = {2024},
publisher = {Damghan University Press},
issn = {2322-4924},
eissn = {2383-403X},
doi = {10.22128/ijaa.2024.759.1175},
abstract = {As an alternative gravity model, we consider an extended Einstein-Maxwell gravity containing a gauge invariance property. An extension is assumed to be an addition of a directional coupling between spatial electromagnetic fields with the Ricci tensor. We will see importance of the additional term in making a compact stellar object and the value of its radius. As an application of this model we substitute ansatz of the magnetic field of a hypothetical magnetic monopole which has just time independent radial component and for matter part we assume a perfect fluid stress tensor. To obtain spherically symmetric internal metric of the perfect fluid stellar compact object we solve the Tolman-Oppenheimer-Volkoff equation with a polytropic form of equation of state as p(ρ) = aρ2. Using dynamical system approach we study stability of the solutions for which arrow diagrams show saddle (quasi stable) for a < 0 (dark stars) and sink (stable) for a > 0 (normal visible stars). We check also the energy conditions, speed of sound and Harrison-Zeldovich-Novikov static stability criterion for obtained solution and confirm that they make stable state.},
keywords = {Magnetic monopoles,stability,stars,Dynamical system,spherical},
url = {https://ijaa.du.ac.ir/article_390.html},
eprint = {https://ijaa.du.ac.ir/article_390_3043c49c5f7689f75b3568e2b216959e.pdf}
}