{
  "id": "2108.13756",
  "version": "v1",
  "published": "2021-08-31T11:11:58.000Z",
  "updated": "2021-08-31T11:11:58.000Z",
  "title": "Formation of Multiple Populations of M5 (NGC 5904)",
  "authors": [
    "Jae-Woo Lee"
  ],
  "comment": "The Astrophysical Journal Letters (in press)",
  "categories": [
    "astro-ph.GA",
    "astro-ph.SR"
  ],
  "abstract": "With our new Ca-CN-CH-NH photometry, we revisit the globular cluster (GC) M5. We find that M5 is a mono-metallic GC with a small metallicity dispersion. Our carbon abundances show that the $\\sigma$[C/Fe] of the M5 CN-s population, with depleted carbon and enhanced nitrogen abundances, is significantly large for a single stellar population. Our new analysis reveals that the M5 CN-s population is well described by the two stellar populations: the CN-s$_{\\rm I}$, being the major CN-s component, with the intermediate carbon and nitrogen abundance and the CN-s$_{\\rm E}$ with the most carbon-poor and nitrogen-rich abundance. We find that the CN-s$_{\\rm E}$ is significantly more centrally concentrated than the others, while CN-w and CN-s$_{\\rm I}$ have similar cumulative radial distributions. The red giant branch bump $V$ magnitude, the helium abundance barometer in mono-metallic populations, of individual populations appears to be correlated with their mean carbon abundance, indicating that carbon abundances are anticorrelated with helium abundances. We propose that the CN-s$_{\\rm E}$ formed out of gas that experienced proton-capture processes at high temperatures in the innermost region of the proto-GC of M5 that resided in a dense ambient density environment. Shortly after, the CN-s$_{\\rm I}$ formed out of gas diluted from the pristine gas in the more spatially extended region, consistent with the current development of numerical simulations by others.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-08-31T11:11:58.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "multiple populations",
      "m5 cn-s population",
      "stellar population",
      "dense ambient density environment",
      "nitrogen abundance"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}