White dwarfs in \(f(\mathcal {R},\mathcal {L}, \mathcal {T})\) gravity

Abstract

Massive white dwarfs have recently been investigated in extended theories of gravity. In the present work, we construct, for the first time, the equilibrium configurations of white dwarfs in the recently proposed \(f(\mathcal {R,L,T})\) theory of gravity, for the specific case \(f(\mathcal {R},\mathcal {L}, \mathcal {T}) = \mathcal {R} + \alpha \mathcal {L} \mathcal {T}\), where \(\alpha \) serves as a free parameter within this gravitational theory, \(\mathcal {R}\) is the Ricci scalar, \(\mathcal {L}\) is the matter Lagrangian density and \(\mathcal {T}\) is the trace of the energy-momentum tensor. We numerically solve the Tolman-Oppenheimer-Volkoff-like and mass equations from a set of boundary conditions and the Chandrasekhar equation of state. We show that it is possible to increase the maximum masses of white dwarfs depending on the value of the theory parameter. What constraints this mass increasing is the value of the central density of the white dwarf. Finally, the theory remarkably recovers general relativity and Newtonian limit for small densities.