Dalessandro, EmanueleEmanueleDalessandroCadelano, M.M.CadelanoVesperini, E.E.VesperiniSalaris, M.M.SalarisFerraro, F. R.F. R.FerraroLanzoni, B.B.LanzoniRaso, S.S.RasoHong, J.J.HongWebb, J. J.J. J.WebbZocchi, A.A.Zocchi2021-02-172021-02-1720180004-637Xhttp://hdl.handle.net/20.500.12386/30438We present a detailed analysis of the radial distribution of light-element multiple populations (LE-MPs) in the massive and dense globular cluster M80, based on a combination of UV and optical Hubble Space Telescope data. Surprisingly, we find that first-generation (FG) stars (FG) are significantly more centrally concentrated than extreme second-generation (SG) stars out to ˜2.5r h from the cluster center. To understand the origin of such peculiar behavior, we used a set of N-body simulations following the long-term dynamical evolution of LE-MPs. We find that, given the advanced dynamical state of the cluster, the observed difference does not depend on the primordial relative distributions of FG and SG stars. On the contrary, a difference of ˜0.05-0.10 M ⊙ between the average masses of the two subpopulations is needed to account for the observed radial distributions. We argue that such a mass difference might be the result of the higher He abundance of SG stars (of the order of ΔY ˜ 0.05-0.06) with respect to FG stars. Interestingly, we find that a similar He variation is necessary to reproduce the horizontal branch morphology of M80. These results demonstrate that differences in mass among LE-MPs, due to different He content, should be properly taken into account for a correct interpretation of their radial distribution, at least in dynamically evolved systems.STAMPAenArticle10.3847/1538-4357/aabb562-s2.0-85047979810000432540700005https://iopscience.iop.org/article/10.3847/1538-4357/aabb562018ApJ...859...15DFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation