The evolution of the mass--radius relation of expanding very young star clusters

Fuente: arXiv
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Main Authors: Zhou, Jian-Wen, Kroupa, Pavel, Wu, Wenjie
Format: Preprint
Published: 2024
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author Zhou, Jian-Wen
Kroupa, Pavel
Wu, Wenjie
author_facet Zhou, Jian-Wen
Kroupa, Pavel
Wu, Wenjie
contents The initial mass--radius relation of embedded star clusters is an essentially important boundary condition for understanding the evolution of embedded clusters in which stars form to their release into the galactic field via an open star cluster phase. The initial mass--radius relation of embedded clusters deduced by Marks \& Kroupa is significantly different from the relation suggested by Pfalzner et al. Here, direct N-body simulations are used to model the early expansion of embedded clusters after the expulsion of their residual gas. The observational data of radii of up to a few~Myr old clusters collated from various sources are found to be well fit by the N-body models, implying these observed very young clusters to most likely be in an expanding state. We show that the mass-radius relation of Pfalzner et al. reflects the expansion of embedded clusters following the initial mass-radius relation of Marks \& Kroupa. We also suggest that even the embedded clusters in ATLASGAL clumps with HII regions are probably already in expansion. All here collected clusters from different observations show a mass-size relation with a similar slope, which may indicate that all clusters were born with a profile resembling that of the Plummer phase-space distribution function.
format Preprint
id arxiv_https___arxiv_org_abs_2409_20271
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The evolution of the mass--radius relation of expanding very young star clusters
Zhou, Jian-Wen
Kroupa, Pavel
Wu, Wenjie
Astrophysics of Galaxies
The initial mass--radius relation of embedded star clusters is an essentially important boundary condition for understanding the evolution of embedded clusters in which stars form to their release into the galactic field via an open star cluster phase. The initial mass--radius relation of embedded clusters deduced by Marks \& Kroupa is significantly different from the relation suggested by Pfalzner et al. Here, direct N-body simulations are used to model the early expansion of embedded clusters after the expulsion of their residual gas. The observational data of radii of up to a few~Myr old clusters collated from various sources are found to be well fit by the N-body models, implying these observed very young clusters to most likely be in an expanding state. We show that the mass-radius relation of Pfalzner et al. reflects the expansion of embedded clusters following the initial mass-radius relation of Marks \& Kroupa. We also suggest that even the embedded clusters in ATLASGAL clumps with HII regions are probably already in expansion. All here collected clusters from different observations show a mass-size relation with a similar slope, which may indicate that all clusters were born with a profile resembling that of the Plummer phase-space distribution function.
title The evolution of the mass--radius relation of expanding very young star clusters
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2409.20271