Eur. Phys. J. C (2017) 77: 871
https://doi.org/10.1140/epjc/s10052-017-5413-5

Regular Article - Theoretical Physics

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

¹ Departamento de Física, Instituto Tecnológico de Aeronáutica, São José dos Campos, SP, 12228-900, Brazil
² Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 5, 00185, Rome, Italy
³ ICRANet, P.zza della Repubblica 10, 65122, Pescara, Italy
⁴ Departamento de Ciencias, Universidad Privada del Norte, Avenida Alfredo Mendiola 6062 Urbanización Los Olivos, Lima, Peru
⁵ Instituto de Formação de Professores, Universidade Federal do Cariri, Brejo Santo, CE, 63260-000, Brazil

^* e-mail: araujogc@ita.br

Received: 9 October 2017
Accepted: 23 November 2017
Published online: 15 December 2017

Abstract

In this work we investigate the equilibrium configurations of white dwarfs in a modified gravity theory, namely, 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 , with 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 are derived. More massive and larger white dwarfs are found for negative values of 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 , namely, .