{
  "id": "1110.1077",
  "version": "v1",
  "published": "2011-10-05T19:17:53.000Z",
  "updated": "2011-10-05T19:17:53.000Z",
  "title": "A Double Main Sequence in the Globular Cluster NGC 6397",
  "authors": [
    "A. P. Milone",
    "A. F. Marino",
    "G. Piotto",
    "L. R. Bedin",
    "J. Anderson",
    "A. Aparicio",
    "S. Cassisi",
    "R. M. Rich"
  ],
  "comment": "19 pages, 11 figures, accepted for pubblication in ApJ",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "High-precision multi-band HST photometry reveals that the main sequence (MS) of the globular cluster NGC 6397 splits into two components, containing ~30% and ~70% of the stars. This double sequence is consistent with the idea that the cluster hosts two stellar populations: (i) a primordial population that has a composition similar to field stars, and containing ~30% of the stars, and (ii) a second generation with enhanced sodium and nitrogen, depleted carbon and oxygen, and a slightly enhanced helium abundance (Delta Y~0.01). We examine the color difference between the two sequences across a variety of color baselines and find that the second sequence is anomalously faint in m_F336W. Theoretical isochrones indicate that this could be due to NH depletion.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2011-10-05T19:17:53.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "globular cluster ngc",
      "double main sequence",
      "high-precision multi-band hst photometry",
      "cluster hosts",
      "stellar populations"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/745/1/27",
      "journal": "The Astrophysical Journal",
      "year": 2012,
      "month": "Jan",
      "volume": 745,
      "number": 1,
      "pages": 27
    },
    "note": {
      "typesetting": "TeX",
      "pages": 19,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 930769,
      "adsabs": "2012ApJ...745...27M"
    }
  }
}