Related papers: Innermost Stable Circular Orbits and Epicyclic Fre…
We investigate the innermost stable circular orbit (ISCO) of a test particle moving on the equatorial plane around rotating relativistic stars such as neutron stars. First, we derive approximate analytic formulas for the angular velocity…
In 1998, Shibata and Sasaki [Phys. Rev. D 58, 104011 (1998)] presented an approximate analytical formula for the radius of the innermost stable circular orbit (ISCO) of a neutral test particle around a massive, rotating and deformed source.…
Exact calculations of innermost stable circular orbit (ISCO) around rotating strange stars are performed within the framework of general relativity. Equations of state (EOS) of strange quark matter based on the MIT Bag Model with massive…
The innermost stable cicular orbit (ISCO) of an accretion disc orbiting a neutron star (NS) is often assumed a unique prediction of general relativity. However, it has been argued that ISCO also appears around highly elliptic bodies…
We study the innermost stable circular orbit (ISCO) of a test particle around rapidly rotating neutron stars. Based on 12 different nuclear-matter equations of state (EOS), we find numerically two approximately EOS-insensitive universal…
We determine the innermost stable circular orbit (ISCO) of binary neutron stars (BNSs) by performing dynamical simulations in full general relativity. Evolving quasiequilibrium (QE) binaries that begin at different separations, we bracket…
Newtonian point mass binaries can be brought into arbitrarily close circular orbits. Neutron stars and black holes, however, are extended, relativistic objects. Both finite size and relativistic effects make very close orbits unstable, so…
We study the dynamics of test particles around a magnetized Ernst black hole considering its magnetic field in the environment surrounding the black hole. We show how its magnetic field can influence the dynamics of particles and epicyclic…
Whether analytic exact vacuum(electrovacuum) solutions of the Einstein(Einstein-Maxwell) field equations can accurately describe or not the exterior spacetime of compact stars remains still an interesting open question in Relativistic…
It has been suggested that the frequency in the co-rotating innermost stable circular orbit (ISCO) about a compact stellar remnant can be determined through X-ray observations of low-mass X-ray binaries, and that its value can be used to…
We investigate the dynamics of charged particles in the spacetime of a global monopole swallowed by a Reissner-Nordstr\"om (RN) black hole in the presence of an external, weak, asymptotically homogeneous magnetic field. We carefully analyze…
We study stability of a circular orbit of a spinning test particle in a Kerr spacetime. We find that some of the circular orbits become unstable in the direction perpendicular to the equatorial plane, although the orbits are still stable in…
Recent X-ray variability observations of accreting neutron stars may provide the first evidence for frame dragging effects around spinning relativistic objects. Motivated by this possibility and its implications for neutron-star structural…
Magnetic fields in an accretion disk around the central black hole can modify the position of the innermost stable circular orbit (ISCO) radius and produces the difference for the classical Novikov-Thorne radius. We estimated the ISCO…
The motion of classical spinning test particles in the equatorial plane of a Kerr black hole is considered for the case where the particle spin is perpendicular to the equatorial plane. We review some results of our recent research of the…
The innermost stable circular orbits (ISCO) of coalescing neutron star-black hole binary are studied taking into account both the tidal and relativistic effects. We adopt the generalized pseudo-Newtonian potential to mimic the general…
The eigen frequencies of radial pulsations of neutron stars are calculated in a strong magnetic field. At low densities we use the magnetic BPS equation of state(EOS) similar to that obtained by Lai and Shapiro while at high densities the…
We study non-geodesic corrections to the quasicircular motion of charged test particles in the field of magnetized slowly rotating neutron stars. The gravitational field is approximated by the Lense-Thirring geometry, the magnetic field is…
The frequencies of the highest-frequency kilohertz QPOs recently discovered in some sixteen neutron stars in low-mass X-ray binary systems are most likely the orbital frequencies of gas in Keplerian orbit around these neutron stars. If so,…
In the modern era of abundant X-ray detections and the increasing momentum of gravitational waves astronomy, tests of General Relativity in strong field regime become increasingly feasible and their importance for probing gravity cannot be…