Please use this identifier to cite or link to this item:
http://hdl.handle.net/10773/36554
Title: | Epicyclic frequencies for a generic ultracompact object |
Author: | Delgado, Jorge F. M. |
Issue Date: | 15-Sep-2022 |
Publisher: | American Physical Society |
Abstract: | Recently, it has been shown that the radial stability of a light-ring (LR) in a spacetime generated by a stationary, axisymmetric, asymptotically flat object with a $\mathbb{Z}_2$ symmetry determines the possibility and radial stability of timelike circular orbits (TCOs) around the LR. In this paper, we generalise this result by also considering the vertical (angular) stability of the orbits through the study of the radial and vertical epicyclic frequencies. We show that the vertical stability of the LR only determines the vertical stability of the TCOs around it. A relation between the sum of the squared epicyclic frequencies and the Ricci tensor is also provided. With such relation, we show that objects with radially and vertically unstable LRs (TCOs) violate the null (strong) energy condition. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/36554 |
DOI: | 10.1103/PhysRevD.106.064054 |
ISSN: | 0556-2821 |
Appears in Collections: | CIDMA - Artigos DMat - Artigos GGDG - Artigos |
Files in This Item:
File | Description | Size | Format | |
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EpicyclicFrequencies.pdf | 454.85 kB | Adobe PDF | View/Open |
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