We have run direct N-body simulations to investigate the impact of stellar evolution and dynamics on the structural properties of young massive (~3×104M⊙) star clusters (SCs) with different metallicities (Z = 1, 0.1, 0.01 Z⊙). Metallicity drives the mass-loss by stellar winds and supernovae (SNe), with SCs losingmoremass at highmetallicity. We have simulated three sets of initial conditions, with different initial relaxation time-scale. We find that the evolution of the half-mass radius of SCs depends on how fast two-body relaxation is with respect to the lifetime of massive stars. If core collapse is slow in comparison with stellar evolution, then mass-loss by stellar winds and SNe is the dominant mechanism driving SC evolution, and metal-rich SCs expand more than metal-poor ones. In contrast, if core collapse occurs on a comparable time-scale with respect to the lifetime of massive stars, then SC evolution depends on the interplay between mass-loss and three-body encounters: dynamical heating by three-body encounters (mass-loss by stellar winds and SNe) is the dominant process driving the expansion of the core in metal-poor (metal-rich) SCs. As a consequence, the half-mass radius of metal-poor SCs expands more than that of metal-rich ones. We also find core radius oscillations, which grow in number and amplitude as metallicity decreases. © 2014 The Authors.

The impact of metallicity-dependent mass-loss versus dynamical heating on the early evolution of star clusters / Trani, Alessandro; Mapelli, Michela; Bressan, Alessandro. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 445:2(2014), pp. 1967-1976. [10.1093/mnras/stu1898]

The impact of metallicity-dependent mass-loss versus dynamical heating on the early evolution of star clusters

Trani, Alessandro;Mapelli, Michela;Bressan, Alessandro
2014-01-01

Abstract

We have run direct N-body simulations to investigate the impact of stellar evolution and dynamics on the structural properties of young massive (~3×104M⊙) star clusters (SCs) with different metallicities (Z = 1, 0.1, 0.01 Z⊙). Metallicity drives the mass-loss by stellar winds and supernovae (SNe), with SCs losingmoremass at highmetallicity. We have simulated three sets of initial conditions, with different initial relaxation time-scale. We find that the evolution of the half-mass radius of SCs depends on how fast two-body relaxation is with respect to the lifetime of massive stars. If core collapse is slow in comparison with stellar evolution, then mass-loss by stellar winds and SNe is the dominant mechanism driving SC evolution, and metal-rich SCs expand more than metal-poor ones. In contrast, if core collapse occurs on a comparable time-scale with respect to the lifetime of massive stars, then SC evolution depends on the interplay between mass-loss and three-body encounters: dynamical heating by three-body encounters (mass-loss by stellar winds and SNe) is the dominant process driving the expansion of the core in metal-poor (metal-rich) SCs. As a consequence, the half-mass radius of metal-poor SCs expands more than that of metal-rich ones. We also find core radius oscillations, which grow in number and amplitude as metallicity decreases. © 2014 The Authors.
2014
445
2
1967
1976
https://doi.org/10.1093/mnras/stu1898
https://arxiv.org/abs/1409.3006
Trani, Alessandro; Mapelli, Michela; Bressan, Alessandro
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/12534
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