Dynamical formation of Gaia neutron star binaries in star clusters as a phase-dependent process
Abstract
Gaia has discovered dormant compact-object binaries in which the compact object shows no observable interaction with its luminous companion. These systems, hereafter Gaia BHs and Gaia NSs for black hole (BH) and neutron star (NS) companions, provide a new probe of compact-object binary formation. These detached systems are difficult to produce through standard isolated binary evolution alone, and their formation pathways remain unclear. Previous N-body studies have shown that Gaia BH-like objects are formed efficiently in star clusters, while Gaia NS-like objects are not. This has been attributed to the BH subsystem dominating the cluster core. We performed direct N-body simulations of 104 M⊙ star clusters in a Galactic tidal field and investigated how NS-main-sequence (NS-MS) binaries form during the late BH-depleted phase. We found that NS-MS binaries satisfying Gaia-sensitive criteria form only after BH depletion. NSs are present in the core throughout the evolution, but the strong encounters there are monopolized by the BH subsystem until it is depleted. Our results show that the dynamical formation of Gaia-sensitive NS-MS systems is not prevented in star clusters, but delayed relative to Gaia BH-like systems.
Related
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BibTeX
@misc{iwakura2026dynamical,
title = {{Dynamical formation of Gaia neutron star binaries in star clusters as a phase-dependent process}},
author = {Ryutaro Iwakura and Long Wang and Ataru Tanikawa and Takayuki R. Saitoh and Yoko Funato and Junichiro Makino},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.09039},
eprint = {2611.09039},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.09039},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Dynamical formation of Gaia neutron star binaries in star clusters as a phase-dependent process
AU - Ryutaro Iwakura
AU - Long Wang
AU - Ataru Tanikawa
AU - Takayuki R. Saitoh
AU - Yoko Funato
AU - Junichiro Makino
PY - 2026
DA - 2026/11/06
PB - arXiv
DO - 10.48550/arxiv.2611.09039
UR - https://arxiv.org/abs/2611.09039
AB - Gaia has discovered dormant compact-object binaries in which the compact object shows no observable interaction with its luminous companion. These systems, hereafter Gaia BHs and Gaia NSs for black hole (BH) and neutron star (NS) companions, provide a new probe of compact-object binary formation. These detached systems are difficult to produce through standard isolated binary evolution alone, and their formation pathways remain unclear. Previous N-body studies have shown that Gaia BH-like objects are formed efficiently in star clusters, while Gaia NS-like objects are not. This has been attributed to the BH subsystem dominating the cluster core. We performed direct N-body simulations of 10^4 M_⊙ star clusters in a Galactic tidal field and investigated how NS-main-sequence (NS-MS) binaries form during the late BH-depleted phase. We found that NS-MS binaries satisfying Gaia-sensitive criteria form only after BH depletion. NSs are present in the core throughout the evolution, but the strong encounters there are monopolized by the BH subsystem until it is depleted. Our results show that the dynamical formation of Gaia-sensitive NS-MS systems is not prevented in star clusters, but delayed relative to Gaia BH-like systems.
ER -