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arXiv · 2302.03951

Revisiting compact star in $F(R)$ gravity: Roles of chameleon potential and energy conditions

Kota Numajiri·Yong-Xiang Cui·Taishi Katsuragawa·Shin'ichi Nojiri
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Abstract

We reexamine the static and spherical symmetric compact star configuration in the $R^2$ model of the $F(R)$ gravity theory. With asymptotic solutions for the additional scalar degrees of freedom, we refine analysis on the external geometry and settle the scalar-hair problem argued in previous works. Performing the numerical integration of the modified Tolman-Oppenheimer-Volkoff equations as a two-boundaries-value problem, we further discuss the scalar-field distribution inside the compact stars and its influence on the mass-radius relation. We show that the chameleon potential plays an essential role in determining the scalar-field profile inside the star. The scalar field often behaves as a quintessential field that effectively decreases the mass of compact stars with lower central energy density.

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Kota Numajiri, Yong-Xiang Cui, Taishi Katsuragawa, Shin'ichi Nojiri. 2023-02-08. Revisiting compact star in $F(R)$ gravity: Roles of chameleon potential and energy conditions. https://doi.org/10.1103/physrevd.107.104019

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