Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption

Stars grazing supermassive black holes on bound orbits may produce periodic flares over many passages, known as repeating partial tidal disruption events (TDEs). Here, we present 3D hydrodynamic simulations of Sun-like stars over multiple tidal encounters. The star is significantly restructured and...

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Main Authors: Chang Liu, Ricardo Yarza, Enrico Ramirez-Ruiz
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ad9b0b
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author Chang Liu
Ricardo Yarza
Enrico Ramirez-Ruiz
author_facet Chang Liu
Ricardo Yarza
Enrico Ramirez-Ruiz
author_sort Chang Liu
collection DOAJ
description Stars grazing supermassive black holes on bound orbits may produce periodic flares over many passages, known as repeating partial tidal disruption events (TDEs). Here, we present 3D hydrodynamic simulations of Sun-like stars over multiple tidal encounters. The star is significantly restructured and becomes less concentrated as a result of mass loss and tidal heating. The vulnerability to mass loss depends sensitively on the stellar density structure, and the strong correlation between the fractional mass loss Δ M / M _* and the ratio of the central and average density ${\rho }_{{\rm{c}}}/\bar{\rho }$ , which was initially derived in disruption simulations of main-sequence stars, also applies for stars strongly reshaped by tides. Over multiple orbits, the star loses progressively more mass in each encounter and is doomed to a complete disruption. Throughout its lifetime, the star may produce numerous weak flares (depending on the initial impact parameter), followed by a couple of luminous flares whose brightness increases exponentially. Flux-limited surveys are heavily biased toward the brightest flares, which may appear similar to the flare produced by the same star undergoing a full disruption on its first tidal encounter. This places new challenges on constraining the intrinsic TDE rates, which need to take repeating TDEs into account. Other types of stars with different initial density structures (e.g., evolved stars with massive cores) follow distinct evolution tracks, which might explain the diversity of the long-term luminosity evolution seen in recently uncovered repeaters.
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spelling doaj-art-676b379969db4fce94eaa4d7cd9004e92025-08-20T03:05:04ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0197914010.3847/1538-4357/ad9b0bRepeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete DisruptionChang Liu0https://orcid.org/0000-0002-7866-4531Ricardo Yarza1https://orcid.org/0000-0003-0381-1039Enrico Ramirez-Ruiz2https://orcid.org/0000-0003-2558-3102Department of Physics and Astronomy, Northwestern University , 2145 Sheridan Rd., Evanston, IL 60208, USA; Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman Ave., Evanston, IL 60201, USADepartment of Astronomy and Astrophysics, University of California , Santa Cruz, CA 95064, USADepartment of Astronomy and Astrophysics, University of California , Santa Cruz, CA 95064, USAStars grazing supermassive black holes on bound orbits may produce periodic flares over many passages, known as repeating partial tidal disruption events (TDEs). Here, we present 3D hydrodynamic simulations of Sun-like stars over multiple tidal encounters. The star is significantly restructured and becomes less concentrated as a result of mass loss and tidal heating. The vulnerability to mass loss depends sensitively on the stellar density structure, and the strong correlation between the fractional mass loss Δ M / M _* and the ratio of the central and average density ${\rho }_{{\rm{c}}}/\bar{\rho }$ , which was initially derived in disruption simulations of main-sequence stars, also applies for stars strongly reshaped by tides. Over multiple orbits, the star loses progressively more mass in each encounter and is doomed to a complete disruption. Throughout its lifetime, the star may produce numerous weak flares (depending on the initial impact parameter), followed by a couple of luminous flares whose brightness increases exponentially. Flux-limited surveys are heavily biased toward the brightest flares, which may appear similar to the flare produced by the same star undergoing a full disruption on its first tidal encounter. This places new challenges on constraining the intrinsic TDE rates, which need to take repeating TDEs into account. Other types of stars with different initial density structures (e.g., evolved stars with massive cores) follow distinct evolution tracks, which might explain the diversity of the long-term luminosity evolution seen in recently uncovered repeaters.https://doi.org/10.3847/1538-4357/ad9b0bTime domain astronomyStellar structuresTidal disruptionSupermassive black holes
spellingShingle Chang Liu
Ricardo Yarza
Enrico Ramirez-Ruiz
Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption
The Astrophysical Journal
Time domain astronomy
Stellar structures
Tidal disruption
Supermassive black holes
title Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption
title_full Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption
title_fullStr Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption
title_full_unstemmed Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption
title_short Repeating Partial Tidal Encounters of Sun-like Stars Leading to Their Complete Disruption
title_sort repeating partial tidal encounters of sun like stars leading to their complete disruption
topic Time domain astronomy
Stellar structures
Tidal disruption
Supermassive black holes
url https://doi.org/10.3847/1538-4357/ad9b0b
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