Milone, A. P.A. P.MiloneMarino, A. F.A. F.MarinoBEDIN, LuigiLuigiBEDINAnderson, J.J.AndersonApai, D.D.ApaiBellini, A.A.BelliniDieball, A.A.DieballSalaris, M.M.SalarisLibralato, M.M.LibralatoNardiello, D.D.NardielloBergeron, P.P.BergeronBurgasser, A. J.A. J.BurgasserRees, J. M.J. M.ReesRich, R. M.R. M.RichRicher, H. B.H. B.Richer2024-01-302024-01-3020190035-8711http://hdl.handle.net/20.500.12386/34670Historically, multiple populations in globular clusters (GCs) have been mostly studied from ultraviolet and optical filters down to stars that are more massive than ∼0.6 M_{\odot }. Here, we exploit deep near-infrared (NIR) photometry from the Hubble Space Telescope to investigate multiple populations among M-dwarfs in the GC NGC 6752. We discovered that the three main populations (A, B, and C), previously observed in the brightest part of the colour-magnitude diagram (CMD), define three distinct sequences that run from the main-sequence (MS) knee towards the bottom of the MS (∼0.15 {M}_{\odot }). These results, together with similar findings on NGC 2808, M 4, and ω Centauri, demonstrate that multiple sequences of M-dwarfs are common features of the CMDs of GCs. The three sequences of low-mass stars in NGC 6752 are consistent with stellar populations with different oxygen abundances. The range of [O/Fe] needed to reproduce the NIR CMD of NGC 6752 is similar to the oxygen spread inferred from high-resolution spectroscopy of red giant branch (RGB) stars. The relative numbers of stars in the three populations of M-dwarfs are similar to those derived among RGB and MS stars more massive than ∼0.6 M_{\odot }. As a consequence, the evidence that the properties of multiple populations do not depend on stellar mass is a constraint for the formation scenarios.STAMPAenArticle10.1093/mnras/stz2772-s2.0-85062281933http://arxiv.org/abs/1901.07230v1https://academic.oup.com/mnras/article/484/3/4046/53014222019MNRAS.484.4046MFIS/05 - ASTRONOMIA E ASTROFISICA