{
  "id": "1901.07230",
  "version": "v1",
  "published": "2019-01-22T09:48:54.000Z",
  "updated": "2019-01-22T09:48:54.000Z",
  "title": "The HST Large Programme on NGC6752. II. Multiple populations at the bottom of the main sequence probed in NIR",
  "authors": [
    "A. P. Milone",
    "A. F. Marino",
    "L. R. Bedin",
    "J. Anderson",
    "D. Apai",
    "A. Bellini",
    "A. Dieball",
    "M. Salaris",
    "M. Libralato",
    "D. Nardiello",
    "P. Bergeron",
    "A. J. Burgasser",
    "J. M. Rees",
    "R. M. Rich",
    "H. B. Richer"
  ],
  "comment": "7 pages, 5 figures, accepted for publication in MNRAS",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "Historically, 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 solar masses. Here we exploit deep near-infrared (NIR) photometry from the Hubble Space Telescope to investigate multiple populations among M-dwarfs in the GC NGC6752. We discovered that the three main populations (A, B and C), previously observed in the brightest part of the color-magnitude diagram, define three distinct sequences that run from the main-sequence (MS) knee towards the bottom of the MS (~0.15 solar masses). These results, together with similar findings on NGC2808, M4, and omega Centauri, demonstrate that multiple sequences of M-dwarfs are common features of the color-magnitude diagrams of GCs. The three sequences of low-mass stars in NGC6752 are consistent with stellar populations with different oxygen abundances. The range of [O/Fe] needed to reproduce the NIR CMD of NGC6752 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 solar masses. As a consequence, the evidence that the properties of multiple populations do not depend on stellar mass is a constraint for the formation scenarios.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-01-22T09:48:54.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "multiple populations",
      "hst large programme",
      "main sequence",
      "solar masses",
      "color-magnitude diagram"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}