Internal structures and circular orbits for test particles

Abstract

We explore how the internal structure of a test particle affects its equatorial stable circular orbits around the Kerr black hole with or without a cosmological constant. To this end, we first explicitly write equations of motion for a test particle in the pole-dipole-quadrupole approximation specifying the quadrupole momentum tensor to a spin-induced model. Then we calculate characteristic quantities -- radius, angular momentum, energy, angular velocity, and impact parameter -- for the particles on the stable circular orbits. Once the pole-dipole-quadrupole approximation is taken, we find that for a particle on an innermost stable circular orbit, all characteristic quantities, except the angular velocity, become greater relative to the pole-dipole case. In contrast, for a particle on an outermost stable circular orbit, which only exists in the case of the spacetime background being asymptotically de Sitter, it is the radius that becomes smaller while all other quantities become greater.

References in corpus (9)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Gravitational self-force correction to the innermost stable circular orbit of a Schwarzschild black hole
• Equatorial circular orbits in the Kerr-de Sitter spacetimes
• Spinning test particles in the $\gamma$ spacetime
• Spinning test-body orbiting around a Kerr black hole: circular dynamics and gravitational-wave fluxes
• Conservative corrections to the innermost stable circular orbit (ISCO) of a Kerr black hole: a new gauge-invariant post-Newtonian ISCO condition, and the ISCO shift due to test-particle spin and the gravitational self-force
• Dynamics of test bodies with spin in de Sitter spacetime
• Properties of the Innermost Stable Circular Orbit of a spinning particle moving in a rotating Maxwell-dilaton black hole background
• Ballistic orbits in Schwarzschild space-time and gravitational waves from EMR binary mergers