Revisiting compact star in 
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 gravity: Roles of chameleon potential and energy conditions

Numajiri, Kota; Cui, Yong-Xiang; Katsuragawa, Taishi; Nojiri, Shin’ichi

doi:10.1103/physrevd.107.104019

Cited by 4 publications

(2 citation statements)

References 69 publications

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“…the review articles [23][24][25][26] for a broader understanding on the subject. Moreover, at a smaller (astrophysical) level, f (R) theories have also been tested using compact stars [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

Moment of inertia and compactness of quark stars within the context of f(R, T, L _m) gravity

Pretel

2024

Phys. Scr.

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Within the metric formalism of f(R, T, L m ) gravity theories, we investigate the hydrostatic equilibrium structure of compact stars taking into account both isotropic and anisotropic pressure. For this purpose, we focus on the f(R, T, L m ) = R + α TL m model, where α is a free parameter. We derive the modified TOV equations and the relativistic moment of inertia in the slowly rotating approximation. Using an equation of state (EoS) for color-superconducting quark stars, we examine the effects of the α TL m term on the different macroscopic properties of these stars. Our results reveal that the decrease of the parameter α leads to a noticeable increase in the maximum-mass values. For negative α with sufficiently small ∣α∣, we obtain a qualitative behavior similar to the general relativistic (GR) context, namely, it is possible to obtain a critical stellar configuration such that the mass reaches its maximum. However, for sufficiently large values of ∣α∣ keeping negative α, the critical point cannot be found on the mass-radius diagram. We also find that the inclusion of anisotropic pressure can provide masses and radii quite consistent with the current observational measurements, which opens an outstanding window onto the physics of anisotropic quark stars. By comparing the I − C relations of isotropic quark stars in modified gravity, we show that such a correlation remains almost unchanged as the parameter α varies from GR counterpart. On the other hand, given a fixed α, the I − C relation is insensitive to variations of the anisotropy parameter β to O ( 4 % ) .

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Section: Introductionmentioning

confidence: 99%

Moment of inertia and compactness of quark stars within the context of f(R, T, L _m) gravity

Pretel

2024

Phys. Scr.

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“…The study of NS in the context of modified gravity theories is an active area of research, as it offers the possibility of testing the predictions of these theories against observational data [24][25][26][27]. In particular, some modified gravity theories predict that NS can have a larger radius than predicted by GR [23,26,[28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Unveiling a universal relationship between the f(R) parameter and neutron star properties

2023

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In recent years, modified gravity theories have gained significant attention as potential replacements for the general theory of relativity. Neutron stars, which are dense compact objects, provide ideal astrophysical laboratories for testing these theories. However, understanding the properties of neutron stars within the framework of modified gravity theories requires careful consideration of the presently known uncertainty of equations of state (EoS) that describe the behavior of matter at extreme densities. In this study, we investigate three realistic EoS generated using a relativistic mean field framework, which covers the currently known uncertainties in the stiffness of neutron star matter. We then employ a Bayesian approach to statistically analyze the posterior distribution of the free parameter α of the fðRÞ gravity model, specifically fðRÞ ¼ R þ αR 2 . By using this approach, we are able to account for our limited understanding of the interiors of neutron stars as well as the uncertainties associated with the modified gravity theory. We impose observational constraints on our analysis, including the maximum mass, and the radius of a neutron star with a mass of 1.4M ⊙ and 2.08M ⊙ , which are obtained from x-ray NICER observations. By considering these constraints, we are able to robustly investigate the relationship between the fðRÞ gravity model parameter α and the maximum mass of neutron stars. Our results reveal a universality relationship between the fðRÞ gravity model parameter α and the maximum mass of neutron stars. This relationship provides insights into the behavior of neutron stars in modified gravity theories and helps us understand the degeneracies arising from our current limited knowledge of the interiors of neutron stars and the free parameter α of the modified gravity theory.

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Compact stars in Rastall gravity: hydrostatic equilibrium and radial pulsations

Pretel,

Mota

2024

Gen Relativ Gravit

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

Cited by 4 publications

References 69 publications

Moment of inertia and compactness of quark stars within the context of f(R, T, L _m) gravity

Moment of inertia and compactness of quark stars within the context of f(R, T, L _m) gravity

Unveiling a universal relationship between the f(R) parameter and neutron star properties

Compact stars in Rastall gravity: hydrostatic equilibrium and radial pulsations

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

Cited by 4 publications

References 69 publications

Moment of inertia and compactness of quark stars within the context of f(R, T, L m ) gravity

Moment of inertia and compactness of quark stars within the context of f(R, T, L m ) gravity

Unveiling a universal relationship between the f(R) parameter and neutron star properties

Compact stars in Rastall gravity: hydrostatic equilibrium and radial pulsations

Contact Info

Product

Resources

About

Moment of inertia and compactness of quark stars within the context of f(R, T, L _m) gravity

Moment of inertia and compactness of quark stars within the context of f(R, T, L _m) gravity