A comparative study between EGB gravity and GTR by modeling compact stars

Bhar, Piyali; Govender, M.; Sharma, Ranjan

doi:10.1140/epjc/s10052-017-4675-2

Cited by 50 publications

(42 citation statements)

References 34 publications

(35 reference statements)

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“…Therefore, in this subsection as a final check we investigate if the energy conditions are fulfilled or not. We require that [68][69][70][71]…”

Section: Numerical Resultsmentioning

confidence: 99%

“…Since now there is one more unknown quantity, to obtain a tractable solution an approach often used in the literature is to assume a concrete and reasonable mass function, see e.g. [71,97]. Then the rest of the quantities may de computed one by one using the EoS as well as the structure equations.…”

Section: Anisotropic Objectsmentioning

confidence: 99%

“…Then the rest of the quantities may de computed one by one using the EoS as well as the structure equations. Following [71] we assume that 2λ(r) = Ar 2 = a(r/r 0 ) 2…”

Section: Anisotropic Objectsmentioning

confidence: 99%

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Relativistic strange quark stars in Lovelock gravity

Panotopoulos

Rincón

2019

Eur. Phys. J. Plus

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We study relativistic non-rotating stars in the framework of Lovelock gravity. In particular, we consider the Gauss-Bonnet term in a five-dimensional spacetime, and we investigate the impact of the Gauss-Bonnet parameter on properties of the stars, both isotropic and anisotropic. For matter inside the star, we assume a relativistic gas of de-confined massless quarks. We integrate the modified Tolman-Oppenheimer-Volkoff equations numerically, and we obtain the mass-to-radius profile, the compactness of the star as well as the gravitational red-shift for several values of the Gauss-Bonnet parameter. The maximum star mass and radius are also reported. PACS. XX.XX.XX No PACS code given 1 IntroductionAlthough our observable Universe is clearly four-dimensional, the question "How many dimensions are there?" is one of the fundamental questions High Energy Physics tries to answer. Kaluza-Klein theories [1,2], supergravity [3] and Superstring/M-Theory [4,5] have pushed forward the idea that extra spatial dimensions may exist. In more than four dimensions higher order curvature terms are natural in Lovelock theory [6], and also higher order curvature corrections appear in the low-energy effective equations of Superstring Theory [7].The amount of published works in the literature reveals that Lovelock gravity is an exciting and active field. Black hole physics [8][9][10][11][12][13][14], cosmological solutions [15][16][17][18] and holographic superconductors exploiting the gauge/gravity duality [19] are some of the areas that have been explored in the framework of Lovelock gravity. However, the astrophysical implications of Lovelock theory should also be investigated. Compact objects [20][21][22], such as white dwarfs and neutron stars, are the final fate of stars, and comprise excellent cosmic laboratories to study, test and constrain new physics and/or alternative theories of gravity under extreme conditions that cannot be reached in Earth-based experiments. It is well-known that the properties of compact objects, such as mass and radius, depend both on the equation-of-state (EoS) of ultra-dense matter and on the underlying theory of gravity.A couple of years after the discovery of the neutron by James Chadwick [23,24], neutron stars were predicted to exist by Baade and Zwicky [25]. Indeed, several decades after that, the discoveries of pulsars in the Crab and Vela supernova remnants [26] led to their identification as neutron stars just one year after the discovery of pulsars in 1967 [27]. On the other hand quark matter is by assumption absolutely stable, and as such it may be the true ground state of hadronic matter [28,29]. Therefore a new class of hypothetical compact objects has been postulated to exist. These compact objects could serve as an alternative to neutron stars, and they might offer us a plausible explanation of the puzzling observation of some super-luminous supernovae [30,31], which occur in about one out of every 1000 supernovae explosions, and which are more than 100 times more luminous than regular su...

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“…Therefore, in this subsection as a final check we investigate if the energy conditions are fulfilled or not. We require that [68][69][70][71]…”

Section: Numerical Resultsmentioning

confidence: 99%

Section: Anisotropic Objectsmentioning

confidence: 99%

See 1 more Smart Citation

Relativistic strange quark stars in Lovelock gravity

Panotopoulos

Rincón

2019

Eur. Phys. J. Plus

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“…Dev and Gleiser [16] proposed several exact solutions for anisotropic stars by taking constant density. We have extensively studied the charged and uncharged model of compact stars in some of our earlier works [17][18][19][20][21][22][23][24][25][26]. To find the exact solution, a more systematic approach is to assume conformal symmetry of the space-time.…”

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confidence: 99%

Effect of electric charge on anisotropic compact stars in conformally symmetric spacetime

et al. 2018

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We obtain a new class of interior solutions for charged anisotropic stars which admits non-static conformal motion. The Einstein-Maxwell field equations are solved by taking a physically reasonable choice for the g rr metric co-efficient and a suitable expression for charge density. From the analysis we have shown that there is a central singularity on space-time by calculating Kretschmann scalar though the central density and central pressure are finite. The emphasis are given on the causality condition and the stability analysis of the model. The masses and radii of the compact stars PSR J16142230, PSR J1903+327 and LMC X-4 obtained from the model are well match with the observed values provided by Gangopadhyay et al (2013 Mon. Not. R. Astron. Soc. 431 3216)

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“…Usually an ansatz for e λ is given, but e ν is used instead sometimes. There are solutions with polynomial metric [95], [96], [97], [98], [99], [100], [101], [102], [103], [104], rational metric [105], [106], [107], [108], [109], [110], [111], [112], [113], exponential one [114], [115], with trigonometric functions [116], [117], [118], [119], [120], [121], [122], [123], [124], [125], [126] hyperbolic [127], [128], [129], [130], [131]. Special functions are also used like the hypergeometric one [132] and the error function [133].…”

Section: Spacetimes Of Embedding Class Onementioning

confidence: 99%

Linear and Riccati equations in generating functions for stellar models in general relativity

Иванов

2020

Eur. Phys. J. Plus

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It is shown that the expressions for the tangential pressure, the anisotropy factor and the radial pressure in the Einstein equations may serve as generating functions for stellar models. The latter can incorporate an equation of state when the expression for the energy density is also used. Other generating functions are based on the condition for the existence of conformal motion (conformal flatness in particular) and the Karmarkar condition for embedding class one metrics. In all these cases the equations are linear first order differential equations for one of the metric components and Riccati equations for the other. The latter may be always transformed into second order homogenous linear differential equations. These conclusions are illustrated by numerous particular examples from the study of stellar models.

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A comparative study between EGB gravity and GTR by modeling compact stars

Cited by 50 publications

References 34 publications

Relativistic strange quark stars in Lovelock gravity

Relativistic strange quark stars in Lovelock gravity

Effect of electric charge on anisotropic compact stars in conformally symmetric spacetime

Linear and Riccati equations in generating functions for stellar models in general relativity

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