# Second-generation star formation in globular clusters of different masses

Abstract : By means of three-dimensional hydrodynamical simulations, we investigate the formation of second-generation (SG) stars in young globular clusters of different masses. We consider clusters with a first generation of asymptotic giant branch (AGB) stars with mass 105 and $10^6\, \mathrm{M}_{\odot }$ moving at constant velocity through a uniform gas with density 10-24 and 10-23 g cm-3. Our set-up is designed to reproduce the encounter of a young cluster with a reservoir of dense gas, e.g. during its orbital motion in the host galaxy. In the low-density models, as a result of the cooling AGB ejecta which collect in the centre, weakly perturbed by the external ram pressure, a compact central He-rich SG stellar component is formed on a time-scale which decreases with increasing initial cluster mass. Our high-density models are subject to stronger ram pressure, which prevents the accumulation of the most He-rich AGB ejecta in the cluster centre. As a result, the SG is more extended and less He-enhanced than in the low-density models. By combining our results with previous simulations, we are able to study relevant, cluster-related scaling relations across a dynamical range of two orders of magnitude in mass (from $10^5$ to $10^7 \, \mathrm{M}_{\odot }$). In agreement with current observationally based estimates, we find positive correlations between the SG-to-total number ratio and maximum He enhancement in SG stars as a function of the initial cluster mass.
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https://hal-insu.archives-ouvertes.fr/insu-03711527
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Submitted on : Friday, July 1, 2022 - 2:06:24 PM
Last modification on : Saturday, July 2, 2022 - 3:40:15 AM

### Citation

A. Yaghoobi, F. Calura, J. Rosdahl, H. Haghi. Second-generation star formation in globular clusters of different masses. Monthly Notices of the Royal Astronomical Society, 2022, 510, pp.4330-4346. ⟨10.1093/mnras/stab3682⟩. ⟨insu-03711527⟩

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