Properties of white dwarf in the modified gravity f(R, T) theory

Abstract

White dwarf (WD) is the final evolutionary state of the main sequence star with an initial mass of up to 8.5-10.6 M⊙. WD is different from neutron stars, it is relatively less compact, but the equation of state (EoS) of WD is relatively more certain. "General relativity" (GR) from Einstein is the standard theory of gravity. Recently, the study of modified theories of gravity has attracted many researchers’ attention because compact stars like WD and neutron stars can be observed for modifications from GR. Compared to neutron stars, studies related to gravity modification for WD are relatively rare. Even though WD is currently observed with a larger mass than the Chandrasekar mass, which cannot be explained based on GR. In this work, we investigated the equilibrium configurations of white dwarfs based on modified gravity theory, namely f(R, T) gravity, R for the Ricci scalar and T for the trace of the energy-momentum tensor, where the theory f (R, T) = R + 2λT with λ being constant. Besides that, we also used realistic EoS proposed by Salpeter. The properties of WD to be investigated, including mass, radius, pressure, and energy density, as well as the dependence of these characteristics on the λ parameter. The results were compared with the other results of observations.