{
  "id": "1807.09815",
  "version": "v1",
  "published": "2018-07-25T18:39:39.000Z",
  "updated": "2018-07-25T18:39:39.000Z",
  "title": "Velocity resolved [O I] 63 $μ$m emission in the HD 50138 circumstellar disk",
  "authors": [
    "G. Sandell",
    "C. Salyk",
    "M. van den Ancker",
    "W. -J. de Wit",
    "E. Chambers",
    "R. Güsten",
    "H. Wiesemeyer",
    "H. Richter"
  ],
  "comment": "7 pages, 5 figures, to be published in ApJ",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "HH 50138 is one of the brightest B[e] stars at a distance of $\\sim$ 380 pc with strong infrared excess. The star was observed in [O I] 63 $\\mu$m and [C II] 158 $\\mu$m with high velocity resolution with upGREAT on SOFIA. The velocity resolved [O I] emission provides evidence for a large gas-disk, $\\sim$ 760 au in size, around HD 50138. Whereas previous interferometric observations give strong evidence for a hot gas and dust disk in Keplerian rotation, our bservations are the first to provide unambiguous evidence for a large warm disk around the star. Herschel/PACS observations showed that the [C II] emission is extended, therefore the [C II] emission most likely originates in an ionized gas shell created by a past outflow event. We confirm the isolated nature of HD 50138. It is far from any star forming region and has low proper motion. Neither is there any sign of a remnant cloud from which it could have formed. The extended disk around the star appears carbon poor. It shows OH and [O I] emission, but no CO. The CO abundance appears to be at least an order of magnitude lower than that of OH. Furthermore $^{13}$CO is enriched by more than a factor of five, confirming that the star is not a Herbig Be star. Finally we note that our high spectral resolution [O I] and [C II] observations provide a very accurate heliocentric velocity of the star, 40.8 $\\pm$ 0.2 km~s$^{-1}$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-07-25T18:39:39.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "circumstellar disk",
      "star appears carbon poor",
      "high velocity resolution",
      "accurate heliocentric velocity",
      "observations"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}