Double progenitor origin of the S-star cluster

Fuente: arXiv
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Hauptverfasser: Verberne, Sill, Rossi, Elena Maria, Koposov, Sergey E., Penoyre, Zephyr, Cavieres, Manuel, Kuijken, Konrad
Format: Preprint
Veröffentlicht: 2025
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author Verberne, Sill
Rossi, Elena Maria
Koposov, Sergey E.
Penoyre, Zephyr
Cavieres, Manuel
Kuijken, Konrad
author_facet Verberne, Sill
Rossi, Elena Maria
Koposov, Sergey E.
Penoyre, Zephyr
Cavieres, Manuel
Kuijken, Konrad
contents The origin of the cluster of S-stars located in the Galactic Centre is tied to the supermassive black hole Sagittarius A*, but exactly how is still debated. In this paper, we investigate whether the Hills mechanism can simultaneously reproduce both the S-star cluster's properties and the observed number of hypervelocity stars. To do so, we forward-model the capture and disruption of binary stars originating from the nuclear star cluster (NSC) and the clockwise disk (CWD). We find that the ratio of evolved to main-sequence S-stars is highly sensitive to the origin of the binaries, and that neither the injection of binaries from the CWD nor from the NSC exclusively can reproduce all observations. However, when considering the injection of binaries from both locations, we are able to reproduce all the observations simultaneously, including the number of observed hypervelocity stars, the evolutionary stage of the S-stars, their luminosity function and the distribution of their semi-major axes. The implications of our findings include that ~90% of hypervelocity stars ejected over the past ~10 Myr should originate from the CWD, that the main-sequence S-stars originated in the CWD, and that the evolved S-stars originated in an old stellar population such as the NSC.
format Preprint
id arxiv_https___arxiv_org_abs_2502_17165
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Double progenitor origin of the S-star cluster
Verberne, Sill
Rossi, Elena Maria
Koposov, Sergey E.
Penoyre, Zephyr
Cavieres, Manuel
Kuijken, Konrad
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
The origin of the cluster of S-stars located in the Galactic Centre is tied to the supermassive black hole Sagittarius A*, but exactly how is still debated. In this paper, we investigate whether the Hills mechanism can simultaneously reproduce both the S-star cluster's properties and the observed number of hypervelocity stars. To do so, we forward-model the capture and disruption of binary stars originating from the nuclear star cluster (NSC) and the clockwise disk (CWD). We find that the ratio of evolved to main-sequence S-stars is highly sensitive to the origin of the binaries, and that neither the injection of binaries from the CWD nor from the NSC exclusively can reproduce all observations. However, when considering the injection of binaries from both locations, we are able to reproduce all the observations simultaneously, including the number of observed hypervelocity stars, the evolutionary stage of the S-stars, their luminosity function and the distribution of their semi-major axes. The implications of our findings include that ~90% of hypervelocity stars ejected over the past ~10 Myr should originate from the CWD, that the main-sequence S-stars originated in the CWD, and that the evolved S-stars originated in an old stellar population such as the NSC.
title Double progenitor origin of the S-star cluster
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2502.17165