SMuK 2021 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 3: Classical GR-2

GR 3.1: Talk

Tuesday, August 31, 2021, 14:00–14:15, H6

Geometrically thick tori around compact objects with a quadrupole moment — •Jan-Menno Memmen and Volker Perlick — Znetrum für angewandte Raumfahrttechnologien und Mikrogravitation, Bremen, Deutschland

We study geometrically thick perfect-fluid tori with constant specific angular momentum, so-called "Polish doughnuts", orbiting deformed compact objects with a quadrupole moment. More specifically, we consider two different asymptotically flat, static and axisymmetric vacuum solutions to Einstein’s field equation with a non-zero quadrupole moment, the q-metric and the Erez-Rosen spacetime. It is our main goal to find features of Polish doughnuts in these two spacetimes which qualitatively distinguish them from Polish doughnuts in the Schwarzschild spacetime. As a main result we find that, for both metrics, there is a range of positive (Geroch-Hansen) quadrupole moments which allows for the existence of double tori. If these double tori fill their Roche lobes completely, their meridional cross-section has the shape of a fish, with the body of the fish corresponding to the outer torus and the fish-tail corresponding to the inner torus. Such double tori do not exist in the Schwarzschild spacetime.