The relativistic mass accretion rate for accretion disk in the equatorial of rapidly rotating neutron stars

Abstract

The accretion process occurs when neutron stars are in a binary system. The hypothesis says that accretion reduces the magnetic field in a neutron star. The correlation between accretion and decrease in the magnetic field is indicated by the magnitude of the magnetic field dynamics and the mass accretion rate. The purpose of this research is to formulate the mass rate of accretion in rapidly rotating neutron stars. The accretion disc is assumed to be at the equator. The method used is theoretical-mathematical analysis. The quantities to be summarized are the Killing vector, 4-vector velocity, the angular velocity, and the Lorentz gamma factor derived from the metric. The metric used is a rapidly rotating neutron star. The rate of mass accretion is calculated from these quantities and the equation for mass sustainability. The equation of mass accretion rate is derived from these variables and the mass conservation equation. The equation of mass accretion rate is affected by the radial velocity of accretion flows and distance between matter and center of a neutron star. The result obtained is covariant with the equation of mass accretion rate for Kerr black holes. The results obtained can provide a dynamic equation for the magnetic field to produce an equation for the decrease in the magnetic field in a rapidly rotating neutron star.