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| Main Authors: | , |
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| Format: | Preprint |
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2022
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2212.09485 |
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| _version_ | 1866929198639087616 |
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| author | Ghaffarnejad, Hossein Naderi, Leyla |
| author_facet | Ghaffarnejad, Hossein Naderi, Leyla |
| contents | As an alternative gravity model we consider an extended Einstein-Maxwell gravity containing a gauge invariance property. Extension is assumed to be 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 value of its radius. As an application of this model we substitute ansatz of 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 Tolman-Oppenheimer-Volkoff equation with a polytropic form of equation of state as $p(ρ)=aρ^2$. 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2212_09485 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Modified Gauge Invariant Einstein Maxwell Gravity and Stability of Spherical perfect fluid Stars with Magnetic Monopoles Ghaffarnejad, Hossein Naderi, Leyla General Relativity and Quantum Cosmology As an alternative gravity model we consider an extended Einstein-Maxwell gravity containing a gauge invariance property. Extension is assumed to be 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 value of its radius. As an application of this model we substitute ansatz of 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 Tolman-Oppenheimer-Volkoff equation with a polytropic form of equation of state as $p(ρ)=aρ^2$. 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. |
| title | Modified Gauge Invariant Einstein Maxwell Gravity and Stability of Spherical perfect fluid Stars with Magnetic Monopoles |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2212.09485 |