2013/01/22 by Mariana Orellana, M. Orellana, Federico García +3 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Geophysics and Gravity Measurements #Pulsars and Gravitational Waves Research #astro-ph.CO #astro-ph.HE #gr-qc
paper · pdf · doi:10.1007/s10714-013-1501-5
9 pages, 12 figures, accepted for publication in General Relativity and Gravitation
arxiv created 2013/01/22 · arxiv updated 2013/01/24 · openalex publication_date 2013/02/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The effects implied for the structure of compact objects by the modification of General Relativity produced by the generalization of the Lagrangian density to the form f(R)=R+αR2, where R is the Ricci curvature scalar, have been recently explored. It seems likely that this squared-gravity may allow heavier Neutron Stars (NSs) than GR. In addition, these objects can be useful to constrain free parameters of modified-gravity theories. The differences between alternative gravity theories is enhanced in the strong gravitational regime. In this regime, because of the complexity of the field equations, perturbative methods become a good choice to treat the problem. Following previous works in the field, we performed a numerical integration of the structure equations that describe NSs in f(R)-gravity, recovering their mass-radius relations, but focusing on particular features that arise from this approach in the profiles of the NS interior. We show that these profiles run in correlation with the second-order derivative of the analytic approximation to the Equation of State (EoS), which leads to regions where the enclosed mass decreases with the radius in a counter-intuitive way. We reproduce all computations with a simple polytropic EoS to separate zeroth-order modified gravity effects.