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| Main Authors: | , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2501.07933 |
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| _version_ | 1866912320097091584 |
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| author | Fernandez, Raul Carpio de la Cruz-Dombriz, Alvaro |
| author_facet | Fernandez, Raul Carpio de la Cruz-Dombriz, Alvaro |
| contents | The so-called Buchdahl limit is not yet fully understood in the context of theories of gravity beyond the Einsteinian framework. In this investigation, we generalize this limit for the case of static, spherically-symmetric, relativistic compact stars in f(R) theories of gravity within the metric formalism. We present a comprehensive analysis that ensures regularity, thermodynamic stability, fulfillment of all required junction conditions, recovery of the Newtonian potential at long distances and a correct extraction of the asymptotic mass. Our results are exemplified for the f(R)=R+ alpha R^2 Starobinsky model and several realistic equations of state describing neutron-star matter. We also compare these results with the case of compact stars immersed ad hoc in an Schwarzschild exterior vacuum, although this scenario does not fulfill all necessary f(R) junction conditions. To test the validity of viable f(R) models, we show that such stars can indeed host additional energetic content, so their gravitational redshift can be greater than 2, which is prohibited in General Relativity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_07933 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Toward a realistic Buchdahl limit in f(R) theories of gravity Fernandez, Raul Carpio de la Cruz-Dombriz, Alvaro General Relativity and Quantum Cosmology The so-called Buchdahl limit is not yet fully understood in the context of theories of gravity beyond the Einsteinian framework. In this investigation, we generalize this limit for the case of static, spherically-symmetric, relativistic compact stars in f(R) theories of gravity within the metric formalism. We present a comprehensive analysis that ensures regularity, thermodynamic stability, fulfillment of all required junction conditions, recovery of the Newtonian potential at long distances and a correct extraction of the asymptotic mass. Our results are exemplified for the f(R)=R+ alpha R^2 Starobinsky model and several realistic equations of state describing neutron-star matter. We also compare these results with the case of compact stars immersed ad hoc in an Schwarzschild exterior vacuum, although this scenario does not fulfill all necessary f(R) junction conditions. To test the validity of viable f(R) models, we show that such stars can indeed host additional energetic content, so their gravitational redshift can be greater than 2, which is prohibited in General Relativity. |
| title | Toward a realistic Buchdahl limit in f(R) theories of gravity |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2501.07933 |