Encounter between an extended hyperelastic body and a Schwarzschild black hole with quadrupole-order effects

Fuente: arXiv
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Main Authors: Jadoo, Nishita, Brown, J. David, Evans, Charles R.
Format: Preprint
Published: 2025
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author Jadoo, Nishita
Brown, J. David
Evans, Charles R.
author_facet Jadoo, Nishita
Brown, J. David
Evans, Charles R.
contents We model the general relativistic interaction of a small hyperelastic sphere with a Schwarzschild black hole as it follows an initially marginally-bound orbit through a close encounter. While the interaction reveals effects that are encoded by the Mathisson-Papapetrou-Dixon (MPD) multipolar equations through quadrupole order, the calculation is made using an independent general relativistic finite element scheme that we described earlier (Phys.~Rev.~D 108(8):084020, October 2023). The finite element calculation is done in Schwarzschild coordinates, following a large and scalable number of mass elements in interaction with each other through elastic forces derived from a potential energy function and with the spacetime geometry. After the fact, we analyze the dynamics using a local Fermi coordinate system, computing (1) the deviation of the center of mass of the body relative to the initial marginally-bound orbit, (2) changes in orbital and spin angular momenta, and (3) the decrease in orbital energy and accompanying deposition of energy into internal elastic dynamics. The interaction leads to the capture of the small body into a highly eccentric orbit ($e \simeq 0.99998$ in a sample calculation).
format Preprint
id arxiv_https___arxiv_org_abs_2511_08699
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Encounter between an extended hyperelastic body and a Schwarzschild black hole with quadrupole-order effects
Jadoo, Nishita
Brown, J. David
Evans, Charles R.
General Relativity and Quantum Cosmology
We model the general relativistic interaction of a small hyperelastic sphere with a Schwarzschild black hole as it follows an initially marginally-bound orbit through a close encounter. While the interaction reveals effects that are encoded by the Mathisson-Papapetrou-Dixon (MPD) multipolar equations through quadrupole order, the calculation is made using an independent general relativistic finite element scheme that we described earlier (Phys.~Rev.~D 108(8):084020, October 2023). The finite element calculation is done in Schwarzschild coordinates, following a large and scalable number of mass elements in interaction with each other through elastic forces derived from a potential energy function and with the spacetime geometry. After the fact, we analyze the dynamics using a local Fermi coordinate system, computing (1) the deviation of the center of mass of the body relative to the initial marginally-bound orbit, (2) changes in orbital and spin angular momenta, and (3) the decrease in orbital energy and accompanying deposition of energy into internal elastic dynamics. The interaction leads to the capture of the small body into a highly eccentric orbit ($e \simeq 0.99998$ in a sample calculation).
title Encounter between an extended hyperelastic body and a Schwarzschild black hole with quadrupole-order effects
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2511.08699