Neutron star models in frames of f (R) gravity

Neutron star models in perturbative f (R) gravity are considered with realistic equations of state. In particular, we consider the FPS and SLy equations of state. The mass-radius relations for f (R) = R + R(e -R/R0 -1) model and for R 2 models with cubic corrections are obtained. In the case of R 2 gravity with cubic corrections, we obtain that at high central densities ( > 10 ns , where ns = 2.7 10 14 g/cm 3 is the nuclear saturation density), stable star configurations exist. The minimal radius of such stars is close to 9 km with maximal mass 1.9M (SLy equation) or to 8.5 km with mass 1.7M (FPS equation). This effect can give rise to more compact stars than in GR. If observationally identified, such objects could constitute a formidable signature for modified gravity at astrophysical level.

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