White Dwarfs in a Uniform Sphere Approximation, with General Relativity Effects Taken into Account

Astrophysics ◽  
2021 ◽  
Author(s):  
G. S. Bisnovatyi-Kogan ◽  
E. A. Patraman
Keyword(s):  
General Relativity ◽  
White Dwarfs ◽  
Sphere Approximation ◽  
Uniform Sphere

The stellar graveyard

2019 ◽  
pp. 177-206
Author(s):  
Nils Andersson
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Stellar Evolution ◽  
White Dwarfs ◽  
Supermassive Black Holes ◽  
Compact Objects ◽  
Fermi Gases ◽  
The 1950S

This chapter introduces the different classes of compact objects—white dwarfs, neutron stars, and black holes—that are relevant for gravitational-wave astronomy. The ideas are placed in the context of developing an understanding of the likely endpoint(s) of stellar evolution. Key ideas like Fermi gases and the Chandrasekhar mass are discussed, as is the emergence of general relativity as a cornerstone of astrophysics in the 1950s. Issues associated with different formation channels for, in particular, black holes are considered. The chapter ends with a discussion of the supermassive black holes that are found at the centre of galaxies.

scholarly journals Relativistic Feynman-Metropolis-Teller theory for white dwarfs in general relativity

2011 ◽  
Vol 84 (8) ◽  
Author(s):  
Michael Rotondo ◽  
Jorge A. Rueda ◽  
Remo Ruffini ◽  
She-Sheng Xue
Keyword(s):  
General Relativity ◽  
White Dwarfs

scholarly journals Conquering systematics in the timing of the pulsar triple system J0337+1715: Towards a unique and robust test of the strong equivalence principle

2017 ◽  
Vol 13 (S337) ◽  
pp. 342-343
Author(s):  
N. V. Gusinskaia ◽  
A. M. Archibald ◽  
J. W. T. Hessels ◽  
D. R. Lorimer ◽  
S. M. Ransom ◽  
...  
Keyword(s):  
General Relativity ◽  
Numerical Integration ◽  
Equivalence Principle ◽  
Triple System ◽  
White Dwarfs ◽  
Radio Pulsar ◽  
Radio Telescopes ◽  
Robust Test ◽  
Millisecond Radio ◽  
Strong Equivalence Principle

AbstractPSR J0337+1715 is a millisecond radio pulsar in a hierarchical stellar triple system with two white dwarfs. This system is a unique and excellent laboratory in which to test the strong equivalence principle (SEP) of general relativity. An initial SEP-violation test was performed using direct 3-body numerical integration of the orbit in order to model the more than 25000 pulse times of arrival (TOAs) from three radio telescopes: Arecibo, Green Bank and Westerbork. In this work I present our efforts to quantify the effects of systematics in the TOAs and timing residuals, which limit the precision of an SEP test. In particular, we apply Fourier-based techniques to the timing residuals in order to isolate the effects of systematics that can masquerade as an SEP violation.

Equilibrium configurations of white dwarfs in the pseudo-complex general relativity

2017 ◽  
Vol 338 (9-10) ◽  
pp. 1085-1089 ◽  
Author(s):  
J. E. S. Costa ◽  
D. Hadjimichef ◽  
M. V. T. Machado ◽  
F. Köpp ◽  
G. L. Volkmer ◽  
...  
Keyword(s):  
General Relativity ◽  
White Dwarfs ◽  
Equilibrium Configurations ◽  
Complex General Relativity

scholarly journals Chandrasekhar's Fluid Dynamics

2019 ◽  
Vol 51 (1) ◽  
pp. 1-24
Author(s):  
Katepalli R. Sreenivasan
Keyword(s):  
Fluid Dynamics ◽  
Black Holes ◽  
General Relativity ◽  
Nobel Prize ◽  
White Dwarfs ◽  
Stellar Structure ◽  
Stability Problems ◽  
Structure And Dynamics ◽  
Brief Assessment ◽  
Subrahmanyan Chandrasekhar

Subrahmanyan Chandrasekhar (1910–1995) is justly famous for his lasting contributions to topics such as white dwarfs and black holes (which led to his Nobel Prize), stellar structure and dynamics, general relativity, and other facets of astrophysics. He also devoted some dozen or so of his prime years to fluid dynamics, especially stability and turbulence, and made important contributions. Yet in most assessments of his science, far less attention is paid to his fluid dynamics work because it is dwarfed by other, more prominent work. Even within the fluid dynamics community, his extensive research on turbulence and other problems of fluid dynamics is not well known. This review is a brief assessment of that work. After a few biographical remarks, I recapitulate and assess the essential parts of this work, putting my remarks in the context of times and people with whom Chandrasekhar interacted. I offer a few comments in perspective on how he came to work on turbulence and stability problems, on how he viewed science as an aesthetic activity, and on how one's place in history gets defined.

scholarly journals Existence of Chandrasekhar’s limit in generalized uncertainty white dwarfs

2021 ◽  
Vol 8 (6) ◽  
pp. 210301
Author(s):  
Arun Mathew ◽  
Malay K. Nandy
Keyword(s):  
General Relativity ◽  
Stability Analysis ◽  
Gravitational Collapse ◽  
White Dwarfs ◽  
Generalized Uncertainty Principle ◽  
Compact Objects ◽  
Dynamical Instability ◽  
Astronomical Observations ◽  
Theoretical Investigations ◽  
Chandrasekhar Limit

The existence of Chandrasekhar’s limit has played various decisive roles in astronomical observations for many decades. However, various recent theoretical investigations suggest that gravitational collapse of white dwarfs is withheld for arbitrarily high masses beyond Chandrasekhar’s limit if the equation of state incorporates the effect of quantum gravity via the generalized uncertainty principle. There have been a few attempts to restore the Chandrasekhar limit but they are found to be inadequate. In this paper, we rigorously resolve this problem by analysing the dynamical instability in general relativity. We confirm the existence of Chandrasekhar’s limit as well as stable mass–radius curves that behave consistently with astronomical observations. Moreover, this stability analysis suggests gravitational collapse beyond the Chandrasekhar limit signifying the possibility of compact objects denser than white dwarfs.

scholarly journals Superdense Stellar Configurations in the Bimetric Scalar-Tensor Theory of Gravity

2018 ◽  
pp. 327-337
Author(s):  
L. Sh. Grigorian ◽  
H. F. Khachatryan ◽  
A. A. Saharian
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Neutron Stars ◽  
White Dwarfs ◽  
Coupling Parameter ◽  
Spherically Symmetric ◽  
Scalar Tensor Theory ◽  
Metric Tensor ◽  
Tensor Theory ◽  
Theory Of Gravity

Models of static spherically-symmetric stellar configurations are discussed within the framework of the Bimetric scalar-tensor theory of gravity. The latter, in addition to the metric tensor and the scalar field, contains a background metric tensor as an absolute variable of the theory. The simplest variant of the theory with a constant coupling parameter and with a zero cosmological function is considered. The analysis includes both the white dwarfs and neutron stars. It is shown that, depending on the value of the theory parameter, the corresponding masses can be notably larger than those in general relativity.

scholarly journals Gravitational decoupling of generalized Horndeski hybrid stars

2022 ◽  
Vol 82 (1) ◽  
Author(s):  
Roldao da Rocha
Keyword(s):  
General Relativity ◽  
Physical Properties ◽  
Neutron Stars ◽  
Observational Data ◽  
White Dwarfs ◽  
Mass Function ◽  
Effective Radius ◽  
Asymptotic Value ◽  
Klein Gordon ◽  
Hybrid Stars

AbstractGravitational decoupled compact polytropic hybrid stars are here addressed in generalized Horndeski scalar-tensor gravity. Additional physical properties of hybrid stars are scrutinized and discussed in the gravitational decoupling setup. The asymptotic value of the mass function, the compactness, and the effective radius of gravitational decoupled hybrid stars are studied for both cases of a bosonic and a fermionic prevalent core. These quantities are presented and discussed as functions of Horndeski parameters, the decoupling parameter, the adiabatic index, and the polytropic constant. Important corrections to general relativity and generalized Horndeski scalar-tensor gravity, induced by the gravitational decoupling, comply with available observational data. Particular cases involving white dwarfs, boson stellar configurations, neutron stars, and Einstein–Klein–Gordon solutions, formulated in the gravitational decoupling context, are also scrutinized.

scholarly journals ON THE MAXIMUM MASS OF GENERAL RELATIVISTIC UNIFORMLY ROTATING WHITE DWARFS

2011 ◽  
Vol 20 (supp01) ◽  
pp. 136-140 ◽  
Author(s):  
KUANTAY BOSHKAYEV ◽  
JORGE RUEDA ◽  
REMO RUFFINI
Keyword(s):  
General Relativity ◽  
Quadrupole Moment ◽  
White Dwarfs ◽  
Rotation Period ◽  
Moment Of Inertia ◽  
Einstein Equations ◽  
Central Density ◽  
Maximum Mass ◽  
General Relativistic ◽  
The Moment

The properties of uniformly rotating white dwarfs are analyzed within the framework of general relativity. Hartle's formalism is applied to construct self-consistently the internal and external solutions to the Einstein equations. The mass, the radius, the moment of inertia and quadrupole moment of rotating white dwarfs have been calculated as a function of both the central density and rotation period of the star. The maximum mass of rotating white dwarfs for stable configurations has been obtained.

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