{
  "id": "1402.2682",
  "version": "v1",
  "published": "2014-02-11T22:01:11.000Z",
  "updated": "2014-02-11T22:01:11.000Z",
  "title": "SMA millimeter observations of Hot Molecular Cores",
  "authors": [
    "Vicente Hernández-Hernández",
    "Luis Zapata",
    "Stan Kurtz",
    "Guido Garay"
  ],
  "comment": "22 pages, 8 figures, Accepted to ApJ",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present Submillimeter Array observations, in the 1.3 mm continuum and the CH_3CN(12-11) line of 17 hot molecular cores associated with young high-mass stars. The angular resolution of the observations ranges from 1\".0 to 4\".0. The continuum observations reveal large (>3500 AU) dusty structures with gas masses from 7 to 375 Msun, that probably surround multiple young stars. The CH_3CN line emission is detected toward all the molecular cores at least up to the K=6-component and is mostly associated with the emission peaks of the dusty objects. We used the multiple K-components of the CH_3CN and both the rotational diagram method and a simultaneous synthetic LTE model with the XCLASS program to estimate the temperatures and column densities of the cores. For all sources, we obtained reasonable fits from XCLASS by using a model that combines two components: an extended and warm envelope, and a compact hot core of molecular gas, suggesting internal heating by recently formed massive stars. The rotational temperatures lie in the range of 40-132 K and 122-485 K for the extended and compact components, respectively. From the continuum and CH_3CN results, we infer fractional abundances from 10^{-9} to 10^{-7} toward the compact inner components, that increase with the rotational temperature. Our results agree with a chemical scenario in which the CH_3CN molecule is efficiently formed in the gas phase above 100-300 K, and its abundance increases with temperature.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-02-11T22:01:11.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hot molecular cores",
      "sma millimeter observations",
      "probably surround multiple young stars",
      "rotational temperature",
      "continuum observations reveal large"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/786/1/38",
      "journal": "The Astrophysical Journal",
      "year": 2014,
      "month": "May",
      "volume": 786,
      "number": 1,
      "pages": 38
    },
    "note": {
      "typesetting": "TeX",
      "pages": 22,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014ApJ...786...38H"
    }
  }
}