White dwarfs in regularized 4D Einstein-Gauss-Bonnet gravity

Abstract

White dwarfs (WDs), as the remnants of low to intermediate-mass stars, provide a unique opportunity to explore the interplay between quantum mechanical degeneracy pressure and gravitational forces under extreme conditions. In this study, we examine the structure and macroscopic properties of WDs within the framework of 4D Einstein-Gauss-Bonnet (4DEGB) gravity, a modified theory that incorporates higher-order curvature corrections through the Gauss-Bonnet coupling constant $\alpha$. Using the modified Tolman-Oppenheimer-Volkoff (TOV) equations tailored for 4DEGB gravity, we analyze the hydrostatic equilibrium of WDs modeled with a realistic equation of state (EoS). Our findings reveal that the inclusion of the Gauss-Bonnet (GB) term significantly influences the mass-radius ($M-R$) relation, allowing for deviations from the Chandrasekhar mass limit. In particular, we observe that such stars become more compact and slightly smaller with the increase of the parameter $\alpha$. For WDs with $|\alpha |\le 500\mathrm{k}{\mathrm{m}}^2$, the impact of 4DEGB gravity appears to be negligible. However, a larger range for $\alpha$ allows for appreciable changes in the $M-R$ diagram, mainly in the high-central-density region. Furthermore, we explore the role of anisotropic pressures, quantified by the parameter $\beta$, on such systems and demonstrate their impact on stability and compactness. For sufficiently large values of $|\beta |$ keeping negative $\beta$ with a large and positive $\alpha$, there exists a second stable branch according to the classical stability criterion $dM/d{\rho }_c>0$. These results suggest that anisotropic WDs in 4DEGB gravity exhibit unique characteristics that distinguish them from their general relativistic counterparts, offering a novel testing ground for modified gravity theories in astrophysical settings.

16 pages, 6 figures. To appear in Physics Letters B

References in corpus (19)

• A Common Explosion Mechanism for Type Ia Supernovae
• Modified theories of Gravity: Why, How and What?
• The 4D Einstein-Gauss-Bonnet Theory of Gravity: A Review
• Radial pulsations and stability of anisotropic stars with quasi-local equation of state
• The 100 pc White Dwarf Sample in the SDSS Footprint
• Current challenges in the physics of white dwarf stars
• Stellar equilibrium configurations of white dwarfs in the $f(R,T)$ gravity
• Strongly magnetized cold electron degenerate gas: Mass-radius relation of the magnetized white dwarf
• The tidal deformability of an anisotropic compact star: Implications of GW170817
• Equilibrium, radial stability and non-adiabatic gravitational collapse of anisotropic neutron stars
• Stability criterion for white dwarfs in Palatini $f(R)$ gravity
• Moment of inertia of slowly rotating anisotropic neutron stars in $f(R,T)$ gravity
• Timescales for detection of super-Chandrasekhar white dwarfs by gravitational wave astronomy
• Anisotropic magnetized white dwarfs: Unifying under- and over-luminous peculiar and standard type Ia supernovae
• Solar System tests and chameleon effect in f (R) gravity
• A rotating white dwarf shows different compositions on its opposite faces
• Cooling Process of White Dwarf Stars in Palatini $f(R)$ Gravity
• Detection of the Temperature Dependence of the White Dwarf Mass-Radius Relation with Gravitational Redshifts
• Exploring Temperature Influences on Gravitational Wave Production in Binary White Dwarfs

Cited by in corpus (1)

• Stellar modeling within regularized 4D Einstein-Gauss-Bonnet gravity in light of current astrophysical constraints