Stellar equilibrium configurations of white dwarfs in the $f(R,T)$ gravity

Abstract

In this work we investigate the equilibrium configurations of white dwarfs in a modified gravity theory, na\-mely, $f(R,T)$ gravity, for which $R$ and $T$ stand for the Ricci scalar and trace of the energy-momentum tensor, respectively. Considering the functional form $f(R,T)=R+2\lambda T$, with $\lambda$ being a constant, we obtain the hydrostatic equilibrium equation for the theory. Some physical properties of white dwarfs, such as: mass, radius, pressure and energy density, as well as their dependence on the parameter $\lambda$ are derived. More massive and larger white dwarfs are found for negative values of $\lambda$ when it decreases. The equilibrium configurations predict a maximum mass limit for white dwarfs slightly above the Chandrasekhar limit, with larger radii and lower central densities when compared to standard gravity outcomes. The most important effect of $f(R,T)$ theory for massive white dwarfs is the increase of the radius in comparison with GR and also $f(R)$ results. By comparing our results with some observational data of massive white dwarfs we also find a lower limit for $\lambda$, namely, $\lambda >-3\times 10^{-4}$.

To be published in EPJC

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• Charged strange star in $f(R,T)$ gravity with linear equation of state
• Stability criterion for white dwarfs in Palatini $f(R)$ gravity
• Gravitational wave echoes from compact stars in $f(\mathcal{R},T)$ gravity
• Timescales for detection of super-Chandrasekhar white dwarfs by gravitational wave astronomy
• Reconstruction of an Observationally Constrained $f(R,T)$ gravity model
• Asymptotically flat vacuum solution in modified theory of Einstein's gravity
• Rip cosmologies, Wormhole Solutions and Big Trip in the $f(T,\mathcal{T})$ theory of gravity
• Weak-field limit of $f(R)$ gravity to unify peculiar white dwarfs
• Investigating the physical and geometrical parameters of the cosmological models with anisotropic background
• Cooling Process of White Dwarf Stars in Palatini $f(R)$ Gravity
• Stellar structure of quark stars in a modified Starobinsky gravity