München 2019 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 14: Poster Session (posters are permanently on display)

GR 14.8: Poster

Thursday, March 21, 2019, 16:30–18:30, HS 6

Off-equatorial orbits as a violation of No-hair theorem — •Leonardo A. Pachon, Andres F. Gutierrez, and Juan L. Restrepo — Universidad de Antioquia, Medellin, Colombia

The problem of describing the motion of a highly-diluted electrically-charged medium when both gravitational and electromagnetic fields are present is widely studied and is of great interest for describing magnetospheres, accretion disks and when investigating chaos in general relativity. Nevertheless, this problem is commonly addressed treating the electromagnetic filed as a perturbation instead of solving the exact Einstein-Maxwell field equations. In this paper, it is considered the coupling between both fields and used a closed solution of the Einstein-Maxwell field equations for a neutron star in order to obtain the dynamics of charged particles orbiting it. This exact description is particularly important in the vicinity of the star where both fields are both strong and alter the geometry of the space time. It is shown here that even for a qualitative description this closed solution has to be used because its closest approximation gives regular dynamics where there is actually a chaotic one. Off-equatorial lobes are found and cases when they are separated, mixed and when they begin to mix are studied. Chaos is found when separated and when mixed in contrast whit the closest approximate solution that only shows chaos when they are mixed. For studying chaos 3-D Poincare surfaces are plotted, in contrast with the 2-D common ones, for a conceptual advantage: in the 3-D surfaces the chaotic an regular regions do not cross each other.