Globular cluster formation from inertial inflows: accreting extremely massive stars as the origin of abundance anomalies
We use the inertial-inflow model of massive star formation to describe the formation of globular clusters (GCs) in turbulent molecular clouds. A key aspect of this model is that the maximum stellar mass scales linearly with cloud mass, such that extremely massive stars (EMSs, 10<sup>3-4</su...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/411743 |
| Acceso en línea: | http://hdl.handle.net/10261/411743 https://api.elsevier.com/content/abstract/scopus_id/105020784522 |
| Access Level: | acceso abierto |
| Palabra clave: | Galaxies: star clusters: general Galaxies: star formation Globular clusters: general Stars: black holes |
| Sumario: | We use the inertial-inflow model of massive star formation to describe the formation of globular clusters (GCs) in turbulent molecular clouds. A key aspect of this model is that the maximum stellar mass scales linearly with cloud mass, such that extremely massive stars (EMSs, 10<sup>3-4</sup> M<inf>⊙</inf>) form in massive GCs (≿ 10<sup>5</sup> M<inf>⊙</inf> ). The total wind mass loss is dominated by accreting EMSs (aEMSs), whose wind mass-loss rates have become comparable to their accretion rates (≿ 10<sup>-2</sup> M<inf>⊙</inf> yr<sup>-1</sup>). These winds pollute the intracluster medium with hot-hydrogen burning yields during GC formation. We propose a parametrized model for the evolution of the stellar mass function during GC formation (∼ 1 − 2 Myr ), accounting for gas inflow, wind mass loss, and mixing of aEMS yields with pristine gas that has initial proto-GC abundances. Low-mass stars (≾ M<inf>⊙</inf> ) form continuously from this mixed gas and their abundances resemble observed abundance trends with GC mass and metallicity, specifically: (i) the helium spread in a typical GC is small ( ∆Y≃ 0.01 ) and increases with GC mass; (ii) the fraction of polluted stars increases with GC mass and metallicity; and (iii) the extent of the Mg–Al anticorrelations is more pronounced in metal-poor and massive GCs. We conclude that GCs formed with a population of EMSs from gas with surface densities ≿ 10<sup>3</sup> M<inf>⊙</inf> pc<sup>-2</sup> and that nitrogen-rich galaxies discovered by the James Webb Space Telescope are dominated by EMS-rich GCs that formed in the earliest phases of galaxy formation. These EMSs may have left behind intermediate-mass black holes with masses above the pair-instability gap (≿ 120 M<inf>⊙</inf>) that could be found with ongoing gravitational wave experiments. |
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