article · The Astrophysical Journal
Modified gravity theories offer alternative descriptions of extreme astrophysical environments where standard gravitational models face limits. This research evaluates a modified gravity framework, f(R, T), which couples spacetime geometry with matter, using observational data from pulsars including Her X-1. By solving relativistic field equations for a spherically symmetric system with specific assumptions about pressure anisotropy and radial metric potential, analytical solutions for density and pressures were established. The findings indicate that matter-geometry coupling allows stars of a given mass to have smaller radii than predicted by general relativity. When evaluated against observational data from 21 pulsars, the model supports pulsar masses reaching up to 3.35 times the mass of the Sun whilst matching expected nuclear saturation densities. The pulsars were categorised into three surface density groups, all proving consistent with having neutron cores without requiring an initial assumption of an equation of state.
Understanding the internal structure of dense stellar remnants like pulsars helps physicists explore the fundamental laws of gravity and the behaviour of matter under extreme physical conditions. Demonstrating that alternative gravity theories can accurately predict stellar masses and sizes without needing assumed matter properties provides new tools to test whether general relativity fully describes the universe.
The abstract does not indicate an application pathway.
AI-generated from the published abstract. Always read the original work before citing.
Abstract Millisecond pulsars are the perfect testable to examine potential matter-geometry coupling and its physical consequences in the context of the recent Neutron Star Interior Composition Explorer discoveries. We apply the field equations of modified gravity, f ( R , T ) = R + α T , to a spherically symmetric spacetime, where R is the Ricci scalar, α is a dimensional parameter, and T is the matter of the geometry. Five unknown functions are present in the output system of differential equations, which consists of three equations. To close the system, we make explicit assumptions about the anisotropy and the radial metric potential, g rr . We then solve the output differential equations and derive the explicit forms of the components of the energy-momentum tensor, i.e., density, radial, and tangential pressures. We look into the possibility that all of the physical parameters in the star can be reexpressed in terms of α and the compactness parameters, C = 2 GM Rc −2 . We show that, for a given mass, the size permitted by Einstein’s general relativity is less due to the matter-geometry coupling in f ( R , T ). The validity of the hypothesis was validated by observations from an extra 21 pulsars. To achieve a surface density that is compatible with a neutron core at nuclear saturation density, the mass–radius curve enables masses up to 3.35 M ⊙ . We emphasize that although there is no assumption of an equation of state, the model fits well with a linear behavior. When comparing the surface densities of these 20 pulsars, we divided them into three groups. We show that these three groups are compatible with neutron cores.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.3847/1538-4357/acd182
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
