The stellar to sub-stellar masses transition in 47 Tuc

Abstract

Context: The study of the Globular Cluster 47 Tuc offers the opportunity to shed new light on the debated issue on the presence of multiple populations in Globular Clusters, as recent results from HST photometry and high-resolution spectroscopy outlined star-to-star differences in the surface chemical composition. Aims: The goal of the present investigation is the interpretation of recent JWST data of the low main sequence of 47 Tuc, in order to explore the stellar to sub-stellar transition, to derive the mass distribution of the individual sources and to disentangle stars from different populations. Methods: Stellar evolution modelling of low-mass stars of metallicity [Fe/H]=-0.78 and oxygen content [O/Fe]=+0.4 and [O/Fe]=0 is used to simulate the evolution of the first and the second generation of the cluster. The comparison between the calculated sequences with the data points is used to characterize the individual objects, to split the different stellar components and to infer the current mass function of the cluster. Results: The first generation of 47 Tuc harbours 45 % of the overall population of the cluster, the remaining 55 % making up the second generation. The transition from the stellar to the sub-stellar domain is found at $0.074M_{\odot }$ and $0.07M_{\odot }$ for the first and second generations, respectively. The mass function of both the stellar generations are consistent with a Kroupa-like profile down to $0.22M_{\odot }$.

12 pages, 8 figures, 3 tables. Accepted for publication on A&A

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