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The string inspired higher dimensional theories suggest modification of Newton's law at submillimeter length scales. Inter-particle distances in white dwarf and neutron stars are $10^{-10} cms$ and $10^{-13} cms$ respectively, and…

Astrophysics · Physics 2010-10-27 Mofazzal Azam , M. Sami

We study the effect of a white dwarf on the spin-down of a cataclysmic variable system using a three-dimensional magnetohydrodynamic numerical model. The model includes the stellar corona, the stellar wind, and the WD mass and magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-03 O. Cohen , J. J. Drake , V. L. Kashyap

Recent observations of several peculiar over- and under-luminous type Ia supernovae infer indirect evidence for the violation of the Chandrasekhar mass-limit by suggesting the existence of super- and sub-Chandrasekhar limiting mass white…

General Relativity and Quantum Cosmology · Physics 2022-01-11 Lupamudra Sarmah , Surajit Kalita , Aneta Wojnar

The equilibrium configuration of white dwarfs composed of a charged perfect fluid are investigated in the context of the $f(R,\mathcal{T})$ gravity, for which $R$ and $\mathcal{T}$ stand for the Ricci scalar and the trace of the…

General Physics · Physics 2020-05-13 F. Rocha , G. A. Carvalho , D. Deb , M. Malheiro

We present constraints on modified gravity from a cosmic shear analysis of the final data release of the Kilo-Degree Survey (KiDS-Legacy) in combination with DESI measurements of baryon acoustic oscillations, eBOSS observations of redshift…

Millisecond pulsars with white dwarf companions have typical eccentricities $e\sim 10^{-6}-10^{-3}$. The eccentricities of helium white dwarfs are explained well by applying the fluctuation-dissipation theorem to convective eddies in their…

Solar and Stellar Astrophysics · Physics 2024-09-23 Yair Cohen , Sivan Ginzburg , Maya Levy , Tal Bar Shalom , Yoav Siman Tov

Recent literature has seen an ongoing discussion on the limiting mass of strongly magnetized white dwarfs, since such objects may prove to be a source of over-luminous type-Ia supernovae. In an earlier paper, we have presented the…

Solar and Stellar Astrophysics · Physics 2016-01-20 Prasanta Bera , Dipankar Bhattacharya

We consider warped five-dimensional thick braneworlds with four-dimensional Poincar\'e invariance originated from bulk scalar matter non-minimally coupled to gravity plus a Gauss-Bonnet term. The background field equations as well as the…

High Energy Physics - Theory · Physics 2012-02-03 Alfredo Herrera-Aguilar , Dagoberto Malagon-Morejon , Refugio Rigel Mora-Luna , Israel Quiros

Magnitude-limited samples have shown that 20-25 per cent of cataclysmic variables contain white dwarfs with magnetic fields of Mega Gauss strength, in stark contrast to the approximately 5 per cent of single white dwarfs with similar…

Solar and Stellar Astrophysics · Physics 2021-02-10 S. G. Parsons , B. T. Gänsicke , M. R. Schreiber , T. R. Marsh , R. P. Ashley , E. Breedt , S. P. Littlefair , H. Meusinger

Context: The astrophysical gravitational wave background (AGWB) is a stochastic gravitational wave (GW) signal that is emitted by different populations of inspiralling binary systems containing compact objects throughout the Universe. In…

High Energy Astrophysical Phenomena · Physics 2024-10-16 Sophie Hofman , Gijs Nelemans

The effect of magnetic fields in the Equations of State (EoS) of compact objects is the splitting of the pressure in two components, one parallel and the other perpendicular to the magnetic field. This anisotropy suggests the necessity of…

High Energy Astrophysical Phenomena · Physics 2019-01-23 D. Alvear Terrero , V. Hernández Mederos , S. López Pérez , D. Manreza Paret , A. Pérez Martínez , G. Quintero Angulo

We study the effects of massive scalar-tensor theories on the internal properties, crystallization, and cooling process of white dwarf stars that might potentially solve observational tensions. We show that these modified gravity theories…

General Relativity and Quantum Cosmology · Physics 2024-08-29 Sofía Vidal , Aneta Wojnar , Laur Järv , Daniela Doneva

The main goal of this work was to measure the masses and radii of white dwarfs that belong to widely separated, common proper motion binaries with non-degenerate companions. These can be assessed, independently from theoretical mass-radius…

In this work we take our cue from the observations of gravitational waves of the GW190814 event which suggests that source of the signals can be ascribed to a compact binary coalescence of a 22.2 to 24.3$ M_{\odot}$ black hole and a compact…

General Relativity and Quantum Cosmology · Physics 2022-10-12 S. K. Maurya , G. Mustafa , M. Govender , Ksh. Newton Singh

In recent years a number of white dwarfs has been observed with very high surface magnetic fields. We can expect that the magnetic field in the core of these stars would be much higher (~ 10^{14} G). In this paper, we analytically study the…

Solar and Stellar Astrophysics · Physics 2012-05-09 Aritra Kundu , Banibrata Mukhopadhyay

This paper investigates the orbital dynamics and gravitational wave radiation characteristics of neutral test particles around a static spherically symmetric charged black hole (BH) in 4D Einstein-Gauss-Bonnet (4D-EGB) gravity theory. We…

General Relativity and Quantum Cosmology · Physics 2026-05-05 Liping Meng , Zhaoyi Xu , Meirong Tang

The mass-radius relation of white dwarfs is largely determined by the equation of state of degenerate electrons, which causes the stellar radius to decrease as mass increases. Here we observationally measure this relation using the…

Solar and Stellar Astrophysics · Physics 2020-08-27 Vedant Chandra , Hsiang-Chih Hwang , Nadia L. Zakamska , Sihao Cheng

Interior structures of stellar objects might have small pressure anisotropy due to several reasons, including rotation and the presence of magnetic fields. Here, retaining the approximation of spherical symmetry, we study the possible role…

Solar and Stellar Astrophysics · Physics 2019-11-06 Shaswata Chowdhury , Tapobrata Sarkar

This paper is the third in a series on tests of gravity using observations of stars and nearby dwarf galaxies. We carry out four distinct tests using published data on the kinematics and morphology of dwarf galaxies, motivated by the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Vinu Vikram , Anna Cabre , Bhuvnesh Jain , Jake VanderPlas

White dwarfs are a class of stars with unique physical properties. They present many challenging problems whose solution requires the application of advanced theories of dense matter, state-of-the-art experimental techniques, and extensive…

Solar and Stellar Astrophysics · Physics 2022-10-26 D. Saumon , S. Blouin , P. -E. Tremblay