English

Escape, bound and capture geodesics in local static coordinates in Schwarzschild spacetime

General Relativity and Quantum Cosmology 2020-03-11 v2

Abstract

The classical geodesics of timelike particles in Schwarzschild spacetime is analyzed according to the particle starting radius rr, velocity vv and angle α\alpha against the radial outward direction in the reference system of an local static observer. The region of escape, bound and capture orbits in the parameter space of (r, v, α)(r,~v,~\alpha) are solved using the three cases of the effective potential. It is found that generally for radius smaller than 4M4M or velocity larger than c/2c/\sqrt{2} there will be no bound orbits. While for fixed radius larger than 4M4M (or velocity smaller than c/2c/\sqrt{2}), as velocity (or radius) increase from zero (or 2M2M), the particle is always captured until a critical value vcrit1v_{\mathrm{crit1}} (or rcrit1r_{\mathrm{crit1}}) when the bound orbit start to appear around α=π/2\alpha=\pi/2 between a double-napped cone structure. As the velocity (or radius) increases to another critical value vcrit2v_{\mathrm{crit2}} (or rcrit2r_{\mathrm{crit2}}) then the bound directions and escape directions in the outward cone become escape directions, leaving only the inward cone separating the capture and bound directions. The angle of this cone will increase to its asymptotic value as velocity (or radius) increases to its asymptotic value. The implication of these results in shadow of black holes formed by massive particles, in black hole accretion and in spacecraft navigation is briefly discussed.

Keywords

Cite

@article{arxiv.1903.12486,
  title  = {Escape, bound and capture geodesics in local static coordinates in Schwarzschild spacetime},
  author = {Yaoguang Wang and Xionghui Liu and Nan Yang and Jiawei Liu and Junji Jia},
  journal= {arXiv preprint arXiv:1903.12486},
  year   = {2020}
}

Comments

26 pages, 10 figures