Masses and radii of anisotropic deformed magnetized white dwarfs at finite temperature in the presence of \({\varvec{\gamma }}\)-metric

Abstract

The effect of finite non-zero temperature on the masses and radii of anisotropic deformed magnetized white dwarfs in the parameterized \(\gamma \)-metric formalism is investigated. The equation of state (EoS) for a relativistic free Fermi gas of electrons surrounding a lattice of nuclei, considering the effects of finite temperature, Landau quantization, and anisotropic pressure is developed. We found stable super-Chandrasekhar masses of white dwarfs (above \({\sim }5\) \(M_{\odot }\)). At a fixed central density and temperature, the masses decrease monotonically as the central magnetic field increases, and equatorial radii increase monotonically. We also observed that the maximum mass and its corresponding equatorial radius decrease with the increase of the central magnetic field. Moreover, the maximum mass occurs at a higher central density as the magnetic field increases. This shows that increasing the magnetic field (hence increasing anisotropy) softens the EoS and makes the star more compact. We also found that the mass and equatorial radius increase with increasing temperature at a fixed central density and central magnetic field strength. This effect is significant for low central magnetic fields and low central densities. In essence, the finite temperature has an opposing effect to that of the magnetic field by decreasing the anisotropy of the system, thereby making the EoS stiffer and the star less compact.