{
  "id": "1604.06192",
  "version": "v1",
  "published": "2016-04-21T06:44:39.000Z",
  "updated": "2016-04-21T06:44:39.000Z",
  "title": "Calibration of evolutionary diagnostics in high-mass star formation",
  "authors": [
    "Sergio Molinari",
    "Manuel Merello",
    "Davide Elia",
    "Riccardo Cesaroni",
    "Leonardo Testi",
    "Thomas Robitaille"
  ],
  "comment": "Astrophysical Journal Letters, Accepted",
  "categories": [
    "astro-ph.GA",
    "astro-ph.SR"
  ],
  "abstract": "The evolutionary classification of massive clumps that are candidate progenitors of high-mass young stars and clusters relies on a variety of independent diagnostics based on observables from the near-infrared to the radio. A promising evolutionary indicator for massive and dense cluster-progenitor clumps is the L/M ratio between the bolometric luminosity and the mass of the clumps. With the aim of providing a quantitative calibration for this indicator we used SEPIA/APEX to obtain CH3C2H(12-11) observations, that is an excellent thermometer molecule probing densities > 10^5 cm^-3 , toward 51 dense clumps with M>1000 solar masses, and uniformly spanning -2 < Log(L/M) < 2.3. We identify three distinct ranges of L/M that can be associated to three distinct phases of star formation in massive clumps. For L/M <1 no clump is detected in CH3C2H , suggesting an inner envelope temperature below 30K. For 1< L/M < 10 we detect 58% of the clumps, with a temperature between 30 and 35 K independently from the exact value of L/M; such clumps are building up luminosity due to the formation of stars, but no star is yet able to significantly heat the inner clump regions. For L/M> 10 we detect all the clumps, with a gas temperature rising with Log(L/M), marking the appearance of a qualitatively different heating source within the clumps; such values are found towards clumps with UCHII counterparts, suggesting that the quantitative difference in T - L/M behaviour above L/M >10 is due to the first appearance of ZAMS stars in the clumps.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-04-21T06:44:39.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high-mass star formation",
      "evolutionary diagnostics",
      "calibration",
      "excellent thermometer molecule probing densities",
      "dense cluster-progenitor clumps"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2016arXiv160406192M"
    }
  }
}