White dwarf structure in $f(R,T,L_m)$ gravity: beyond the Chandrasekhar mass limit

Abstract

In this work, we investigate the relativistic structure of white dwarfs (WDs) within the framework of modified gravity theory $f(R,T,L_m)=R+\alpha T{L}_m$, which introduces a non-minimal coupling between matter and curvature. Using a realistic equation of state (EoS) that includes contributions from a relativistic degenerate electron gas and ionic lattice effects, we solve the modified Tolman-Oppenheimer-Volkoff (TOV) equations for two standard choices of the matter Lagrangian density: $L_m=p$ and $L_m=-\rho$. We show that the extra $\alpha T{L}_m$ term significantly alters the mass-radius relation of WDs, especially at high central densities $({\rho }_c\gtrsim 10^8-10^{9}g/c{\mathrm{m}}^3)$, allowing for stable super-Chandrasekhar configurations. In particular, depending on the sign and magnitude of the parameter $\alpha$, the maximum mass can increase or decrease, and in some regimes, the usual critical point indicating the transition from stability to instability disappears. Our findings suggest that $f(R,T,L_m)$ gravity provides a viable framework to explain the existence of massive WDs beyond the classical Chandrasekhar limit. Using Bayesian inference with WD observational data, we further constrain the coupling parameter $\alpha$ for the two choices of the Lagrangian density $L_m$.

arXiv comment11 pages, 5 figures and 1 table. To appear in Physics Letters B

References in corpus (53)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• emcee: The MCMC Hammer
• f(R) Theories Of Gravity
• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• f(R) theories
• Extended Theories of Gravity
• f(R,T) gravity
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• Modified gravity with negative and positive powers of the curvature: unification of the inflation and of the cosmic acceleration
• Resummation of Massive Gravity
• Cosmological Tests of Modified Gravity
• f(R,L_m) gravity
• The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star
• Dark Energy Dominance and Cosmic Acceleration in First Order Formalism
• Nearby Supernova Factory Observations of SN 2007if: First Total Mass Measurement of a Super-Chandrasekhar-Mass Progenitor
• f(R, T, R_μνT^μν) gravity phenomenology and ΛCDM universe
• The Sirius System and its Astrophysical Puzzles: Hubble Space Telescope and Ground-Based Astrometry
• The Luminous and Carbon-Rich Supernova 2006gz: A Double Degenerate Merger?
• Hubble Space Telescope Astrometry of the Procyon System
• Modified theories of Gravity: Why, How and What?
• Fourteen Months of Observations of the Possible Super-Chandrasekhar Mass Type Ia Supernova 2009dc
• High luminosity, slow ejecta and persistent carbon lines: SN 2009dc challenges thermonuclear explosion scenarios
• Early phase observations of extremely luminous Type Ia Supernova 2009dc
• New mass limit for white dwarfs: super-Chandrasekhar type Ia supernova as a new standard candle
• Stellar equilibrium configurations of white dwarfs in the $f(R,T)$ gravity
• A highly magnetised and rapidly rotating white dwarf as small as the Moon
• Generalizing the coupling between geometry and matter: $f(R,L_m,T)$ gravity
• Strongly magnetized cold electron degenerate gas: Mass-radius relation of the magnetized white dwarf
• On general relativistic uniformly rotating white dwarfs
• Effects of strong magnetic fields and rotation on white dwarf structure
• Constraints on Modified Gravity Models from White Dwarfs
• Maximum mass of stable magnetized highly super-Chandrasekhar white dwarfs: stable solutions with varying magnetic fields
• Stability of super-Chandrasekhar magnetic white dwarfs
• Neutron stars in $f(R,L_m,T)$ gravity
• Modified Einstein's gravity as a possible missing link between sub- and super-Chandrasekhar type Ia supernovae
• White dwarfs in de Rham-Gabadadze-Tolley like massive gravity
• Modified Einstein's gravity to probe the sub- and super-Chandrasekhar limiting mass white dwarfs: a new perspective to unify under- and over-luminous type Ia supernovae
• Astrophysical Implications of a New Dynamical Mass for the Nearby White Dwarf 40 Eridani B
• Stability criterion for white dwarfs in Palatini $f(R)$ gravity
• Non-minimal geometry-matter couplings in Weyl-Cartan space-times: $f(R,T,Q,T_m)$ gravity
• One possible solution of peculiar type Ia supernovae explosions caused by a charged white dwarf
• Anisotropic quark stars in $f(R,L_m,T)$ gravity
• White dwarf stars in modified gravity
• Metric-affine effects in crystallization processes of white dwarfs
• Anisotropic magnetized white dwarfs: Unifying under- and over-luminous peculiar and standard type Ia supernovae
• Study of the charged super-Chandrasekhar limiting mass white dwarfs in the $f(R,\mathcal{T})$ gravity
• White dwarfs with a surface electrical charge distribution: Equilibrium and stability
• Significantly super-Chandrasekhar mass-limit of white dwarfs in noncommutative geometry
• On the Maximum Mass of General Relativistic Uniformly Rotating White Dwarfs
• Weak-field limit of $f(R)$ gravity to unify peculiar white dwarfs
• Moment of inertia and compactness of quark stars within the context of $f(R,T,L_m)$ gravity
• Properties of white dwarfs in Einstein-$\Lambda$ gravity
• White dwarfs in regularized 4D Einstein-Gauss-Bonnet gravity