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Main Authors: Yu, Fangyuan, Lai, Dong
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2409.09597
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author Yu, Fangyuan
Lai, Dong
author_facet Yu, Fangyuan
Lai, Dong
contents In galactic centers, stars and binaries can be injected into low-angular-momentum orbits, resulting in close encounters with the central supermassive black hole (SMBH). Previous works have shown that under different conditions, such close encounters can lead to the break-up of the binary, disruptions of both stars and collision between the stars. We use 3-body scattering experiments to characterize these different outcomes for a range of system parameters, such as $β_b$, the ratio of binary tidal radius to pericenter distance $r_p$ to the SMBH and the compactness of the binary. We focus on stellar collisions, which occur for a range of $β_b$'s, with a few to 10's percent probabilities (depending on the compactness of the binary). In gentle encounters ($β_b\lesssim 1$), stellar collisions occur after the pericenter passage, and the merger remnants are typically ejected from the SMBH at a small velocity. In deep encounters ($β_b\gtrsim 1$), collisions occur near the pericenter, with the impact velocity a few times the escape velocity of the star, and the merger remnants are typically bound to the SMBH. We suggest that stellar collisions induced by binary-SMBH encounters may produce exotic stars in galactic centers, trigger accretion flares onto the SMBH due to the mass loss, and result in bound merger remnants causing repeated partial TDEs.
format Preprint
id arxiv_https___arxiv_org_abs_2409_09597
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Binary Stars Approaching Supermassive Black Holes: Tidal Break-up, Double Stellar Disruptions and Stellar Collision
Yu, Fangyuan
Lai, Dong
High Energy Astrophysical Phenomena
In galactic centers, stars and binaries can be injected into low-angular-momentum orbits, resulting in close encounters with the central supermassive black hole (SMBH). Previous works have shown that under different conditions, such close encounters can lead to the break-up of the binary, disruptions of both stars and collision between the stars. We use 3-body scattering experiments to characterize these different outcomes for a range of system parameters, such as $β_b$, the ratio of binary tidal radius to pericenter distance $r_p$ to the SMBH and the compactness of the binary. We focus on stellar collisions, which occur for a range of $β_b$'s, with a few to 10's percent probabilities (depending on the compactness of the binary). In gentle encounters ($β_b\lesssim 1$), stellar collisions occur after the pericenter passage, and the merger remnants are typically ejected from the SMBH at a small velocity. In deep encounters ($β_b\gtrsim 1$), collisions occur near the pericenter, with the impact velocity a few times the escape velocity of the star, and the merger remnants are typically bound to the SMBH. We suggest that stellar collisions induced by binary-SMBH encounters may produce exotic stars in galactic centers, trigger accretion flares onto the SMBH due to the mass loss, and result in bound merger remnants causing repeated partial TDEs.
title Binary Stars Approaching Supermassive Black Holes: Tidal Break-up, Double Stellar Disruptions and Stellar Collision
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2409.09597