Are the ONC, Pleiades, and Hyades snapshots of the same embedded cluster?

Fuente: arXiv
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Main Authors: Safaei, Ghasem, Haghi, Hosein, Zonoozi, Akram Hasani, Kroupa, Pavel
Format: Preprint
Published: 2025
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author Safaei, Ghasem
Haghi, Hosein
Zonoozi, Akram Hasani
Kroupa, Pavel
author_facet Safaei, Ghasem
Haghi, Hosein
Zonoozi, Akram Hasani
Kroupa, Pavel
contents Using direct $N$-body simulations, we investigate the initial conditions and evolution of a star-forming region resembling the Orion Nebula Cluster (ONC) with the advanced \textsc{NBODY6} code. By varying the initial conditions, we aim to identify a model that closely aligns with observed parameters such as the half-mass radius, core radius, and total mass. Additionally, we examine the cluster's evolution over 800 Myr to determine whether it could reproduce the present-day properties of the Pleiades and Hyades along its evolutionary path. Under the influence of a Milky Way-like tidal field, the ONC experiences significant mass loss, primarily due to rapid gas expulsion, retaining approximately 47\% of its initial 4200 stars by about 100 Myr and only 9\% by about 700 Myr. These evolutionary stages closely match the properties of the Pleiades and Hyades, suggesting that an ONC-like cluster may have been their precursor. Additional models with varying degrees of primordial mass segregation indicate that the ONC likely had an initial half-mass radius of 0.2-0.3 pc, a total mass of 1200 - 2000 M$_\odot$, and a high degree of mass segregation. Models with an initial stellar count of about $N_{\text{in}} \approx 4 \times 10^3 - 5 \times 10^3$, rich in binaries and exhibiting mass segregation, show excellent agreement with observed cluster properties.
format Preprint
id arxiv_https___arxiv_org_abs_2507_12531
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Are the ONC, Pleiades, and Hyades snapshots of the same embedded cluster?
Safaei, Ghasem
Haghi, Hosein
Zonoozi, Akram Hasani
Kroupa, Pavel
Astrophysics of Galaxies
Using direct $N$-body simulations, we investigate the initial conditions and evolution of a star-forming region resembling the Orion Nebula Cluster (ONC) with the advanced \textsc{NBODY6} code. By varying the initial conditions, we aim to identify a model that closely aligns with observed parameters such as the half-mass radius, core radius, and total mass. Additionally, we examine the cluster's evolution over 800 Myr to determine whether it could reproduce the present-day properties of the Pleiades and Hyades along its evolutionary path. Under the influence of a Milky Way-like tidal field, the ONC experiences significant mass loss, primarily due to rapid gas expulsion, retaining approximately 47\% of its initial 4200 stars by about 100 Myr and only 9\% by about 700 Myr. These evolutionary stages closely match the properties of the Pleiades and Hyades, suggesting that an ONC-like cluster may have been their precursor. Additional models with varying degrees of primordial mass segregation indicate that the ONC likely had an initial half-mass radius of 0.2-0.3 pc, a total mass of 1200 - 2000 M$_\odot$, and a high degree of mass segregation. Models with an initial stellar count of about $N_{\text{in}} \approx 4 \times 10^3 - 5 \times 10^3$, rich in binaries and exhibiting mass segregation, show excellent agreement with observed cluster properties.
title Are the ONC, Pleiades, and Hyades snapshots of the same embedded cluster?
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2507.12531