Buchdahl limit of compact stars in presence of Weyl anomaly
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arXiv
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866912677892194304 |
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| author | Hanafy, Waleed El Nashed, G. G. L. |
| author_facet | Hanafy, Waleed El Nashed, G. G. L. |
| contents | We setup an anisotropic compact star model in presence of Weyl ``trace" anomaly. We derive an exact interior solution which determines the contribution of the vacuum trace anomaly. We introduce a dimentionless parameter, $β$, to characterize this contribution. Applying appropriate matching conditions with the exterior solution, we determine the model parameters in terms of the Weyl anomaly parameter $β$ and the compactness parameter, $C=\frac{2GM}{c^2 \mathcal{R}}$ where $M$ and $\mathcal{R}$ are the mass and the radius of the star. We investigate the parameter space $\{β, C\}$ and the corresponding modifications of Buchdahl limit on the maximum compactness. We use astrophysical observations of mass and radius of the pulsar PSR J0740+6620 to constrain the Weyl anomaly parameter $β$. Also, we investigate the Mass-Radius diagram with other observational constraints from NICER and LIGO/Virgo collaboration. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_21422 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Buchdahl limit of compact stars in presence of Weyl anomaly Hanafy, Waleed El Nashed, G. G. L. General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory We setup an anisotropic compact star model in presence of Weyl ``trace" anomaly. We derive an exact interior solution which determines the contribution of the vacuum trace anomaly. We introduce a dimentionless parameter, $β$, to characterize this contribution. Applying appropriate matching conditions with the exterior solution, we determine the model parameters in terms of the Weyl anomaly parameter $β$ and the compactness parameter, $C=\frac{2GM}{c^2 \mathcal{R}}$ where $M$ and $\mathcal{R}$ are the mass and the radius of the star. We investigate the parameter space $\{β, C\}$ and the corresponding modifications of Buchdahl limit on the maximum compactness. We use astrophysical observations of mass and radius of the pulsar PSR J0740+6620 to constrain the Weyl anomaly parameter $β$. Also, we investigate the Mass-Radius diagram with other observational constraints from NICER and LIGO/Virgo collaboration. |
| title | Buchdahl limit of compact stars in presence of Weyl anomaly |
| topic | General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2509.21422 |