{
  "id": "1310.8087",
  "version": "v2",
  "published": "2013-10-30T10:02:01.000Z",
  "updated": "2014-01-09T23:30:26.000Z",
  "title": "Multi-Object and Long-Slit Spectroscopy of Very Low Mass Brown Dwarfs in Orion Nebular Cluster",
  "authors": [
    "Takuya Suenaga",
    "Motohide Tamura",
    "Masayuki Kuzuhara",
    "Kenshi Yanagisawa",
    "Miki Ishii",
    "Philip W. Lucas"
  ],
  "comment": "Accepted for publication in Publications of the Astronomical Society of Japan",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "We present the results of a H- and K-band multi-object and long-slit spectroscopic survey of substellar mass candidates in the outer regions of the Orion Nebula Cluster. The spectra were obtained using MOIRCS on the 8.2-m Subaru telescope and ISLE on the 1.88-m telescope of Okayama Astronomical Observatory. Eight out of twelve spectra show strong water absorptions and we confirm that their effective temperatures are < 3000 K (spectral type > M6) from a chi-square fit to synthetic spectra. We plot our sources on an HR diagram overlaid with theoretical isochrones of low-mass objects and identify three new young brown dwarf candidates. One of the three new candidates is a cool object near the brown dwarf and planetary mass boundary. Based on our observations and those of previous studies, we determine the stellar (0.08 < M/Msun < 1) to substellar (0.03 < M/Msun < 0.08) mass number ratio in the outer regions of the Orion nebular cluster to be 3.5 +/- 0.8. In combination with the number ratio reported for the central region (3.3+0.8/-0.7), this result suggests the number ratio does not simply change with the distance from the center of the Orion nebular cluster.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2014-01-09T23:30:26.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "orion nebular cluster",
      "low mass brown dwarfs",
      "long-slit spectroscopy",
      "number ratio",
      "multi-object"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1093/pasj/psu016",
      "journal": "Publications of the Astronomical Society of Japan",
      "year": 2014,
      "month": "Apr",
      "volume": 66,
      "number": 2,
      "pages": 33
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1263289,
      "adsabs": "2014PASJ...66...33S"
    }
  }
}