# Einstein-Maxwell field equations in isotropic coordinates: an application to neutron star and quark star

Research paper by N. Pradhan, Neeraj Pant

Indexed on: 01 Apr '14Published on: 01 Apr '14Published in: Astrophysics and Space Science

#### Abstract

We present a new class of static spherically symmetric exact solutions of the Einstein-Maxwell field equations in isotropic coordinates for perfect fluid by considering a specific choice of electrical intensity which involves a parameter K. The resulting solutions represent charged fluid spheres joining smoothly with the Reissner-Nordstrom metric at the pressure free interface. The solutions so obtained are utilized to construct the models for super-dense star like neutron stars (ρb=2 and 2.7×1014 g/cm3) and Quark stars (ρb=4.6888×1014 g/cm3). It is observed that the models are well behaved for the restricted value of parameter K (0.141≤K≤0.159999). Corresponding to Kmax=0.159999 for which, umax=0.259, the resulting Quark star has a maximum mass M=1.618 M⊙ and radius R=9.263 km and the neutron star modeling based on the particular solution; corresponding to K=0.15, u=0.238 and by assuming the surface density ρb=2.7×1014 g/cm3 the maximum mass of neutron star M=1.966 M⊙ and radius R=12.23 km and by assuming the surface density ρb=2×1014 g/cm3 the resulting well behaved solution has a maximum mass of neutron M=2.284 M⊙ and radius R=14.21 km. The robustness of our result is that it matches with the recent discoveries.