General relativistic calculations for white dwarfs

Mathew, Arun; Nandy, Malay K.

doi:10.1088/1674-4527/17/6/61

Cited by 23 publications

(16 citation statements)

References 33 publications

(45 reference statements)

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“…The inverse beta decay instability has recently been taken into account in the calculations within the general relativity framework in Refs. [12] and [65]. The critical density ρ rel crit for the onset of the gravitational collapse, also obtained in these calculations, differs for the iron WDs by a factor ≈ 22, which illustrates the size of model dependence in the astrophysical calculations.…”

Section: Introductionsupporting

confidence: 57%

“…The critical density ρ rel crit for the onset of the gravitational collapse, also obtained in these calculations, differs for the iron WDs by a factor ≈ 22, which illustrates the size of model dependence in the astrophysical calculations. Besides, the calculations of ρ rel crit [12,65] do not take into account the strong magnetic fields. Therefore, the comparison of the derived ρ rel crit [12] with the densities of the SMWDs made in the last but one paragraph at p. 5 of Ref.…”

Section: Introductionmentioning

confidence: 99%

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Consequence of total lepton number violation in strongly magnetized iron white dwarfs

et al. 2015

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Section: Introductionsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Consequence of total lepton number violation in strongly magnetized iron white dwarfs

et al. 2015

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“…Turning to the static case, our main aim in the present work is to show that general relativistic effects are relevant for the determination of the radius of massive WD. In fact, there are some works where general relativistic calculations of the mass-radius relation were made for a static model of WD [32,33,34,35,36]. In those works authors find that general relativistic hydrostatic equilibrium yields to a maximum mass slightly below the Chandrasekhar limiting mass.…”

mentioning

confidence: 99%

General relativistic effects in the structure of massive white dwarfs

2018

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In this work we investigate the structure of white dwarfs using the Tolman-Oppenheimer-Volkoff equations and compare our results with those obtained from Newtonian equations of gravitation in order to put in evidence the importance of General Relativity (GR) for the structure of such stars. We consider in this work for the matter inside white dwarfs two equations of state, frequently found in the literature, namely, the Chandrasekhar and Salpeter equations of state. We find that using Newtonian equilibrium equations, the radii of massive white dwarfs (M > 1.3M ) are overestimated in comparison with GR outcomes. For a mass of 1.415M the white dwarf radius predicted by GR is about 33% smaller than the Newtonian one. Hence, in this case, for the surface gravity the difference between the general relativistic and Newtonian outcomes is about 65%. We depict the general relativistic massradius diagrams as M/M = R/(a + bR + cR 2 + dR 3 + kR 4 ), where a, b, c and d are parameters obtained from a fitting procedure of the numerical results and k = (2.08×10 −6 R ) −1 , being R the radius of the Sun in km. Lastly, we point out that GR plays an important role to determine any physical quantity that depends, simultaneously, on the mass and radius of massive white dwarfs.

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“…The critical values of central density in the case of carbon WD were found to be of the same order for both effects (2.65 · 10 13 and 3.90 · 10 13 kg/m 3 , respectively) [48]. The recent values for general theory of relativity effects are very similar (see, for example [49]). The corresponding values of relativistic parameter interesting to point out, that these constrains are close to the ones, obtained in work [50], where we've used current precision of the measuring gravitating mass in the Solar System to constrain the value of the speed of sound of the dark energy.…”

Section: B Constraintsmentioning

confidence: 61%

White dwarfs as a probe of dark energy

2020

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We investigate the radial density distribution of the dynamical dark energy inside the white dwarfs (WDs) and its possible impact on their intrinsic structure. The minimally-coupled dark energy with barotropic equation of state which has three free parameters (density, equation of state and effective sound speed) is used. We analyse how such dark energy affects the mass-radius relation for the WDs because of its contribution to the joint gravitational potential of the system. For this we use Chandrasekhar model of the WDs, where model parameters are the parameter of the chemical composition and the relativistic parameter. To evaluate the dark energy distribution inside a WD we solve the conservation equation in the spherical static metric. Obtained distribution is used to find the parameters of dark energy for which the deviation from the Chandrasekhar model massradius relation become non-negligible. We conclude also, that the absence of observational evidence for existence of WDs with untypical intrinsic structure (mass-radius relation) gives us lower limit for the value of effective sound speed of dark energy c 2 s 10 −4 (in units of speed of light).

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General relativistic calculations for white dwarfs

Abstract: The mass-radius relations for white dwarf stars are investigated by solving the Newtonian as well as Tolman-Oppenheimer-Volkoff (TOV) equations for hydrostatic equilibrium assuming the electron gas to be non-interacting. We find that the Newtonian limiting mass of 1.4562M

Cited by 23 publications

References 33 publications

Consequence of total lepton number violation in strongly magnetized iron white dwarfs

Consequence of total lepton number violation in strongly magnetized iron white dwarfs

General relativistic effects in the structure of massive white dwarfs

White dwarfs as a probe of dark energy

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