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Related papers: White dwarf stars in modified gravity

200 papers

We explore a new paradigm to study dissipative dark matter models using gravitational-wave observations. We consider a dark atomic model which predicts the formation of binary black holes such as GW190425 while obeying constraints from…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-11 Divya Singh , Michael Ryan , Ryan Magee , Towsifa Akhter , Sarah Shandera , Donghui Jeong , Chad Hanna

Mass-varying massive gravity allows the graviton mass to vary according to different environments. We investigate neutron star and white dwarf solutions in this theory and find that the graviton mass can become very large near the compact…

General Relativity and Quantum Cosmology · Physics 2020-03-31 Xue Sun , Shuang-Yong Zhou

White dwarfs are the dense, burnt-out remnants of the vast majority of stars, condemned to cool over billions of years as they steadily radiate away their residual thermal energy. To first order, their atmosphere is expected to be made…

Solar and Stellar Astrophysics · Physics 2024-05-03 Antoine Bédard

The discovery of $19$ dwarf galaxies without dark matter provides, counter-intuitively, strong support for the $\Lambda$CDM standard model of cosmology. Their presence is well accommodated in a scenario where the dark matter is in the form…

General Relativity and Quantum Cosmology · Physics 2022-01-24 Ali Rida Khalifeh , Raul Jimenez

We study the impact of the chameleon mechanism on the structure of white dwarfs. Using a shooting method of our design, we solve the corresponding scalar-tensor equilibrium equations for a Chandrasekhar equation of state, exploring various…

General Relativity and Quantum Cosmology · Physics 2025-08-05 Joan Bachs-Esteban , Ilídio Lopes , Javier Rubio

The field equations of a generalized $f(R)$ type gravity model, in which there is an arbitrary coupling between matter and geometry, are obtained. The equations of motion for test particles are derived from a variational principle in the…

General Relativity and Quantum Cosmology · Physics 2009-05-26 T. Harko

We consider metric-affine scenarios where a modified gravitational action is sourced by electrovacuum fields in a three dimensional space-time. Such scenarios are supported by the physics of crystalline structures with microscopic defects…

General Relativity and Quantum Cosmology · Physics 2015-08-13 Cosimo Bambi , M. Ghasemi-Nodehi , D. Rubiera-Garcia

We calculate the expected white dwarf luminosity functions and discovery functions in photometric passbands, if these stellar remnants provide a substantial fraction of the sought Galactic dark matter, as suggested on various observational…

Astrophysics · Physics 2009-10-31 Gilles Chabrier

We present an analytical model for the evolution of brown dwarfs in quadratic Palatini f(R) gravity. We improve previous studies by adopting a more realistic description of the partially-degenerate state that characterizes brown dwarfs.…

General Relativity and Quantum Cosmology · Physics 2021-03-24 María Benito , Aneta Wojnar

The existence of a dark energy component has usually been invoked as the most plausible way to explain the recent observational results. However, it is also well known that effects arising from new physics (e.g., extra dimensions) can mimic…

Astrophysics · Physics 2007-05-23 Abha Dev , J. S. Alcaniz , Deepak Jain

There are a few different mechanisms that can cause white dwarf stars to vary in brightness, providing opportunities to probe the physics, structures, and formation of these compact stellar remnants. The observational characteristics of the…

Solar and Stellar Astrophysics · Physics 2025-02-20 Keaton J. Bell

A white dwarf star achieves its equilibrium from the balancing of the gravitational compression against the Fermi degeneracy pressure of the electron gas. In field theory there are examples (e.g. the monopole-charge system) where a strong…

Astrophysics · Physics 2009-11-07 Jerzy Dryzek , Akira Kato , Gerardo Munoz , Douglas Singleton

We review various modified gravities considered as gravitational alternative for dark energy. Specifically, we consider the versions of $f(R)$, $f(G)$ or $f(R,G)$ gravity, model with non-linear gravitational coupling or string-inspired…

High Energy Physics - Theory · Physics 2009-09-17 S. Nojiri , S. D. Odintsov

White dwarfs are the remnants of stars not massive enough to become supernovae. This review explores the concept of strange dwarfs, a unique class of white dwarfs which contain cores of strange quark matter. Strange dwarfs have different…

Solar and Stellar Astrophysics · Physics 2024-12-06 Francesco Di Clemente , Alessandro Drago , Giuseppe Pagliara

To the best of our knowledge, there are no specific calculations of gravity-darkening exponents for white dwarfs in the literature. On the other hand, the number of known eclipsing binaries whose components are tidally and/or rotationally…

Solar and Stellar Astrophysics · Physics 2021-04-28 A. Claret

By applying the Palatini approach to the 1/R-gravity model it is possible to explain the present accelerated expansion of the Universe. Investigation of the late Universe limiting case shows that: (i) due to the curvature effects the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Gilberto M. Kremer , Daniele S. M. Alves

Motivated by the possibility that the fundamental ``constants'' of nature could vary with time, this paper considers the long term evolution of white dwarf stars under the combined action of proton decay and variations in the gravitational…

Astrophysics · Physics 2009-11-13 Jacob A. Ketchum , Fred C. Adams

White dwarf stars are the most common final stage of stellar evolution. Since the serendipitous discovery of the first white dwarf by William Herschel and the first physical models by Subrahmanyan Chandrasekhar and Arthur Eddington, there…

Solar and Stellar Astrophysics · Physics 2025-02-28 Ingrid Pelisoli , Jamie Williams

We summarize recent improvements in model atmosphere and internal structure of faint white dwarfs. We derive an analytical cooling theory which illustrates the effects of various physical processes on the energy budget and the cooling…

Astrophysics · Physics 2007-05-23 Gilles Chabrier