Pulsar slow-down and the temporal change of G

Heintzmann, H.; Hillebrandt, W.

doi:10.1016/0375-9601(75)90764-1

Cited by 46 publications

(55 citation statements)

References 4 publications

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“…Heintzmann and Hillebrandt (1975) modeled the pulsar by a polytropic (P ∝ ρ n ) white dwarf and deduced that d ln I/d ln G = 2 − 3n/2 so that |Ġ/G| < 10 −10 yr −1 .…”

Section: Pulsarsmentioning

confidence: 99%

The fundamental constants and their variation: observational and theoretical status

2003

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This article describes the various experimental bounds on the variation of the fundamental constants of nature. After a discussion on the role of fundamental constants, of their definition and link with metrology, the various constraints on the variation of the fine structure constant, the gravitational, weak and strong interactions couplings and the electron to proton mass ratio are reviewed. This review aims (1) to provide the basics of each measurement, (2) to show as clearly as possible why it constrains a given constant and (3) to point out the underlying hypotheses. Such an investigation is of importance to compare the different results, particularly in view of understanding the recent claims of the detections of a variation of the fine structure constant and of the electron to proton mass ratio in quasar absorption spectra. The theoretical models leading to the prediction of such variation are also reviewed, including KaluzaKlein theories, string theories and other alternative theories and cosmological implications of these results are discussed. The links with the tests of general relativity are emphasized.

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“…Heintzmann and Hillebrandt (1975) modeled the pulsar by a polytropic (P ∝ ρ n ) white dwarf and deduced that d ln I/d ln G = 2 − 3n/2 so that |Ġ/G| < 10 −10 yr −1 .…”

Section: Pulsarsmentioning

confidence: 99%

The fundamental constants and their variation: observational and theoretical status

2003

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“…For an anisotropic fluid sphere Γ can be represented as Γ r and Γ t , the radial adiabatic index and tangential adiabatic index respectively [132]. Chan et al [119] and Heinzmann [133] predicted that adiabatic index should exceed 4 3 inside an anisotropic, relativistic and dynamically stable stellar system. Γ r and Γ t can be expressed mathematically as follows…”

Section: Adiabatic Indexmentioning

confidence: 99%

Anisotropic strange star with Tolman–Kuchowicz metric under f(R, T) gravity

et al. 2020

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In the current article, we study anisotropic spherically symmetric strange star under the background of f (R, T ) gravity using the metric potentials of Tolman-Kuchowicz type [1,2] as λ(r) = ln(1 + ar 2 + br 4 ) and ν(r) = Br 2 + 2 ln C which are free from singularity, satisfy stability criteria and also well behaved. We calculate the value of constants a, b, B and C using matching conditions and the observed values of the masses and radii of known samples. To describe the strange quark matter (SQM) distribution, here we have used the phenomenological MIT bag model equation of state (EOS) where the density profile (ρ) is related to the radial pressure (p r ) as p r (r) = 1 3 (ρ − 4B g ). Here quark pressure is responsible for generation of bag constant B g . Motivation behind this study lies in finding out a nonsingular physically acceptable solution having various properties of strange stars. The model shows consistency with various energy conditions, TOV equation, Herrera's cracking condition and also with Harrison-Zel ′ dovich-Novikov's static stability criteria. Numerical values of EOS parameter and the adiabatic index also enhance the acceptability of our model.

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“…Chandrasekhar [46] studied the dynamical stability of relativistic stars against infinitesimal radial adiabatic perturbation. Heintzmann and Hillebrandt [47] found that an anisotropic compact object will achieve stability if the adiabatic index is greater than 4 3 everywhere inside the con- figuration. The expression for adiabatic index for our system is given by…”

Section: Stability Of Stellar Systemmentioning

confidence: 99%

Anisotropic strange stars through embedding technique in massive Brans–Dicke gravity

Sharif

Majid

2020

Eur. Phys. J. Plus

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This paper investigates the existence and properties of anisotropic strange quark stars in the context of massive Brans-Dicke theory. The field equations are constructed in Jordan frame by assuming a suitable potential function with MIT bag model. We employ the embedding class-one approach as well as junction conditions to determine the unknown metric functions. Radius of the strange star candidate, LMC X-4, is predicted through its observed mass for different values of the bag constant. We analyze the effects of coupling parameter as well as mass of scalar field on state determinants and execute multiple checks on the stability and viability of the spherical system. It is concluded that the resulting stellar structure is physically viable and stable as it satisfies the energy conditions as well as essential stability criteria.

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Pulsar slow-down and the temporal change of G

Cited by 46 publications

References 4 publications

The fundamental constants and their variation: observational and theoretical status

The fundamental constants and their variation: observational and theoretical status

Anisotropic strange star with Tolman–Kuchowicz metric under f(R, T) gravity

Anisotropic strange stars through embedding technique in massive Brans–Dicke gravity

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