The chirping of Lense-Thirring precession in tidal disruption event accretion flows
Abstract
Tidal disruption event X-ray light curves do not appear to show clear signs of periodic modulation. This is naively somewhat surprising since the stars that are disrupted originate at large scales in the galaxy where they cannot know about the orientation of the black hole spin axis. This should lead to the formation of a misaligned disk that precesses due to Lense-Thirring torques, modulating X-ray emission from the inner disk regions. We argue that in fact the properties which are required for solid-body precession, namely a thick (H/R∼ 𝒪(1)) disk, naturally lead to rapid precession period change, with a per-period increase of ΔTprec/Tprec ∼ 𝒪(1−10), as the disk spreads to larger radii to conserve angular momentum. In other words the precession of thick TDE disks is aggressively chirped, washing out any possibility of observing multiple cycles other than for fine tuned regions of parameter space. The global disk alignment timescale is equally strongly chirped by the exact same mechanism, meaning that TDE disks will not in general align with the black hole spin axis during a super-Eddington phase, and should generically show global quasi-steady warp profiles at the beginning of any thin disk phase. These results have important implications for interpreting timing features associated with TDE disks, including models for quasi-periodic X-ray eruption timing phenomenology, and the observational properties of TDE disks in the initial transition to the thin disk phase.
Related
- Operator‑Spectral Geometry of Rotational Gravity: χ‑Modular Curvature, Spectral Flow, and the Precision Lense–Thirring Measurement of LARES‑2
- Disc breaking and parametric instability in warped accretion discs driven by differential precession
- Electromagnetic alignment and jet precession around supermassive black holes: Quasi-periodic oscillations in tidal disruption events
- Observational signatures of warped accretion flows in tidal disruption events
- Time-dependent Accretion Disks in Tidal Disruption Events: Long-term Light Curves
BibTeX
@misc{mummery2026chirping,
title = {{The chirping of Lense-Thirring precession in tidal disruption event accretion flows}},
author = {Andrew Mummery and Eliot Quataert},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22559},
eprint = {2609.22559},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22559},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The chirping of Lense-Thirring precession in tidal disruption event accretion flows
AU - Andrew Mummery
AU - Eliot Quataert
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.22559
UR - https://arxiv.org/abs/2609.22559
AB - Tidal disruption event X-ray light curves do not appear to show clear signs of periodic modulation. This is naively somewhat surprising since the stars that are disrupted originate at large scales in the galaxy where they cannot know about the orientation of the black hole spin axis. This should lead to the formation of a misaligned disk that precesses due to Lense-Thirring torques, modulating X-ray emission from the inner disk regions. We argue that in fact the properties which are required for solid-body precession, namely a thick (H/R∼ 𝒪(1)) disk, naturally lead to rapid precession period change, with a per-period increase of ΔT_prec/T_prec ∼ 𝒪(1−10), as the disk spreads to larger radii to conserve angular momentum. In other words the precession of thick TDE disks is aggressively chirped, washing out any possibility of observing multiple cycles other than for fine tuned regions of parameter space. The global disk alignment timescale is equally strongly chirped by the exact same mechanism, meaning that TDE disks will not in general align with the black hole spin axis during a super-Eddington phase, and should generically show global quasi-steady warp profiles at the beginning of any thin disk phase. These results have important implications for interpreting timing features associated with TDE disks, including models for quasi-periodic X-ray eruption timing phenomenology, and the observational properties of TDE disks in the initial transition to the thin disk phase.
ER -