Fate of the remnant in tidal stripping event: repeating and non-repeating

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Main Authors: Chen, Jin-Hong, Dai, Lixin, Liu, Shang-Fei, Ou, Jian-Wen
Format: Preprint
Published: 2024
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author Chen, Jin-Hong
Dai, Lixin
Liu, Shang-Fei
Ou, Jian-Wen
author_facet Chen, Jin-Hong
Dai, Lixin
Liu, Shang-Fei
Ou, Jian-Wen
contents Tidal disruption events (TDE) occur when a star ventures too close to a massive black hole. In a partial TDE (pTDE), the star only grazes the tidal radius, causing the outer envelope of the star to be stripped away while the stellar core survives. Previous research has shown that a star, once tidally stripped in a parabolic orbit, can acquire enough orbital energy for its remnant to become a high-velocity star potentially capable of escaping the galaxy. Conversely, some studies have reported that the remnant may lose orbital energy and undergo re-disruption, leading to a recurring pTDE. This study aims to uncover the physical mechanisms and determine the conditions that lead to these divergent outcomes. We find that the orbital energy change only depends on the impact factor and the stellar structure, and barely depends on the mass of the black hole or the exact mass or orbital eccentricity of the star. For a $γ=5/3$ (or $γ=4/3$) polytropic star, after a pTDE its remnant gains orbital energy when the impact factor $β\gtrsim 0.62$ (or $\gtrsim 1.1$) or loses energy vice versa. Additionally, we verify an analytical equation for orbital energy change that is applicable across various systems. Through hydrodynamic simulations, we also explore the structure of the stellar remnant post-tidal stripping. Our findings provide critical insights for interpreting observed pTDEs and advancing knowledge on the orbital evolution and event rate of these events.
format Preprint
id arxiv_https___arxiv_org_abs_2408_10925
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fate of the remnant in tidal stripping event: repeating and non-repeating
Chen, Jin-Hong
Dai, Lixin
Liu, Shang-Fei
Ou, Jian-Wen
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
Tidal disruption events (TDE) occur when a star ventures too close to a massive black hole. In a partial TDE (pTDE), the star only grazes the tidal radius, causing the outer envelope of the star to be stripped away while the stellar core survives. Previous research has shown that a star, once tidally stripped in a parabolic orbit, can acquire enough orbital energy for its remnant to become a high-velocity star potentially capable of escaping the galaxy. Conversely, some studies have reported that the remnant may lose orbital energy and undergo re-disruption, leading to a recurring pTDE. This study aims to uncover the physical mechanisms and determine the conditions that lead to these divergent outcomes. We find that the orbital energy change only depends on the impact factor and the stellar structure, and barely depends on the mass of the black hole or the exact mass or orbital eccentricity of the star. For a $γ=5/3$ (or $γ=4/3$) polytropic star, after a pTDE its remnant gains orbital energy when the impact factor $β\gtrsim 0.62$ (or $\gtrsim 1.1$) or loses energy vice versa. Additionally, we verify an analytical equation for orbital energy change that is applicable across various systems. Through hydrodynamic simulations, we also explore the structure of the stellar remnant post-tidal stripping. Our findings provide critical insights for interpreting observed pTDEs and advancing knowledge on the orbital evolution and event rate of these events.
title Fate of the remnant in tidal stripping event: repeating and non-repeating
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2408.10925