Properties of white dwarfs in Einstein-Λ gravity

Abstract

In this paper, we explore the properties of white dwarfs with the modified TOV equation in Einstein-$\Lambda$ gravity, the equilibrium configurations predict a maximum mass limit for white dwarfs same as the Chandrasekhar limit when we consider $\Lambda$ to be very small($\Lambda<10^{-16}$ m$^{-2}$), by increasing $\Lambda$, the maximum mass and radius of white dwarf are reduced. We study effects of the cosmological constant on the physical properties of white dwarf such as $M-\rho_c$ relation, $M-R$ relation, Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability. The gravitational redshift is a decreasing function of cosmological constant, because the gravitational redshift of white dwarf should be positive, we also find an upper limit for $\Lambda$, namely, $\Lambda<3\times10^{-14}$ m$^{-2}$. Our investigation of dynamical stability shown that the white dwarfs follow the dynamical stability in Einstein-$\Lambda$ gravity.