Neutron and quark stars in f(R) gravity

Astashenok, Artyom V.

doi:10.1142/s2010194516601307

Cited by 19 publications

(12 citation statements)

References 27 publications

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“…In this work, however, the mass scales are just two free parameters and we shall not consider the aforementioned values. Strange stars in R 2 gravity have also been studied in [19,20], but in the Einstein frame, while in this article we work in the Jordan frame and in the Palatini formalism. a) Starobinsky model: For a model of the form f (R) = R + R 2 /(6M 2 ) the functions we need are found to be…”

Section: Numerical Results In Two Concrete Modelsmentioning

confidence: 99%

Strange stars in f(R) theories of gravity in the Palatini formalism

Panotopoulos

2017

Gen Relativ Gravit

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In the present work we study strange stars in f (R) theories of gravity in the Palatini formalism.We consider two concrete well-known cases, namely the R+R 2 /(6M 2 ) model as well as the R−µ 4 /R model for two different values of the mass parameter M or µ. We integrate the modified TolmanOppenheimer-Volkoff equations numerically, and we show the mass-radius diagram for each model separately. The standard case corresponding to the General Relativity is also shown in the same figure for comparison. Our numerical results show that the interior solution can be vastly different depending on the model and/or the value of the parameter of each model. In addition, our findings imply that i) for the cosmologically interesting values of the mass scales M, µ the effect of modified gravity on strange stars is negligible, while ii) for the values predicting an observable effect, the modified gravity models discussed here would be ruled out by their cosmological effects.

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Section: Numerical Results In Two Concrete Modelsmentioning

confidence: 99%

Strange stars in f(R) theories of gravity in the Palatini formalism

Panotopoulos

2017

Gen Relativ Gravit

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“…The first time to use a quadratic form of the Ricci scalar was given by Starobinsky [35]. It was shown that the higher-order curvature of f (R) gravity can solve the issue of the massive neutron stars [36][37][38][39][40]. It is well-known that f (R) gravity is consists of an arbitrary function whose first order is the Ricci scalar.…”

Section: Introductionmentioning

confidence: 99%

Higher Dimensional Charged Black Hole Solutions in f(R) Gravitational Theories

Nashed

2018

Advances in High Energy Physics

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We present, without any assumption, a class of electric and magnetic flat horizon -dimension solutions for a specific class of ( ) = + 2 , all of which behave asymptotically as Anti-de-Sitter spacetime. The most interesting property of these solutions is that the higher dimensions black holes, > 4, always have constant electric and magnetic charges in contrast to what is known in the literature. For = 4, we show that the magnetic field participates in the metric on equal foot as the electric field participates. Another interesting result is the fact that the Cauchy horizon is not identical with the event horizon. We use Komar formula to calculate the conserved quantities. We study the singularities and calculate the Hawking temperature and entropy and show that the first law of thermodynamics is always satisfied.

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“…Eventually, a plenty of different models have been proposed to explain various other aspects of observations in astrophysics [20]. Capozziello and his collabo-rators showed that by means of Starobinsky's f (R) gravity and its higher order corrections, the problem of massive neutron stars can easily be explained [18,21,22,23,24]. Similarly, Mukhopadhyay and his collaborators also showed that these models can also explain both the classes of the white dwarfs, viz.…”

Section: Introductionmentioning

confidence: 99%

Asymptotically flat vacuum solution in modified theory of Einstein’s gravity

Kalita

Mukhopadhyay

2019

Eur. Phys. J. C

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A number of recent observations have suggested that the Einstein's theory of general relativity may not be the ultimate theory of gravity. The f (R) gravity model with R being the scalar curvature turns out to be one of the best bet to surpass the general relativity which explains a number of phenomena where Einstein's theory of gravity fails. In the f (R) gravity, behaviour of the spacetime is modified as compared to that of given by the Einstein's theory of general relativity. This theory has already been explored for understanding various compact objects such as neutron stars, white dwarfs etc. and also describing evolution of the universe. Although, researchers have already found the vacuum spacetime solutions for the f (R) gravity, yet there is a caveat that the metric does have some diverging terms and hence these solutions are not asymptotically flat. We show that it is possible to have asymptotically flat spherically symmetric vacuum solution for the f (R) gravity, which is different from the Schwarzschild solution. We use this solution for explaining various bound orbits around the black hole and eventually, as an immediate application, in the spherical accretion flow around it.

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Neutron and quark stars in f(R) gravity

Cited by 19 publications

References 27 publications

Strange stars in f(R) theories of gravity in the Palatini formalism

Strange stars in f(R) theories of gravity in the Palatini formalism

Higher Dimensional Charged Black Hole Solutions in f(R) Gravitational Theories

Asymptotically flat vacuum solution in modified theory of Einstein’s gravity

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