{
  "id": "1302.1892",
  "version": "v2",
  "published": "2013-02-07T21:59:52.000Z",
  "updated": "2013-02-12T19:38:54.000Z",
  "title": "Formation of giant planets and brown dwarfs on wide orbits",
  "authors": [
    "Eduard I. Vorobyov"
  ],
  "comment": "16 pages, 12 figures, accepted for publication in Astronomy & Astrophysics",
  "categories": [
    "astro-ph.EP",
    "astro-ph.SR"
  ],
  "abstract": "Context: We studied numerically the formation of giant planet (GP) and brown dwarf (BD) embryos in gravitationally unstable protostellar disks and compared our findings with directly-imaged, wide-orbit (>= 50 AU) companions known to-date. The viability of the disk fragmentation scenario for the formation of wide-orbit companions in protostellar disks around (sub-)solar mass stars was investigated. Methods: We used numerical hydrodynamics simulations of disk formation and evolution with an accurate treatment of disk thermodynamics. The use of the thin-disk limit allowed us to probe the long-term evolution of protostellar disks. We focused on models that produced wide-orbit GP/BD embryos, which opened a gap in the disk and showed radial migration timescales similar to or longer than the typical disk lifetime. Results: While disk fragmentation was seen in the majority of our models, only 6 models out of 60 revealed the formation of quasi-stable, wide-orbit GP/BD embryos. Disk fragmentation produced GP/BD embryos with masses in the 3.5-43 M_J range, covering the whole mass spectrum of directly-imaged, wide-orbit companions to (sub-)solar mass stars. On the other hand, our modelling failed to produce embryos on orbital distances <= 170 AU, whereas several directly-imaged companions were found at smaller orbits down to a few AU. Disk fragmentation also failed to produce wide-orbit companions around stars with mass <= 0.7 Msun, in disagreement with observations. Conclusions: Disk fragmentation is unlikely to explain the whole observed spectrum of wide-orbit companions to (sub-)solar-mass stars and other formation mechanisms, e.g., dynamical scattering of closely-packed companions onto wide orbits, should be invoked to account for companions at orbital distance from a few tens to \\approx 150 AU and wide-orbit companions with masses of the host star <= 0.7 Msun. (abridged)",
  "revisions": [
    {
      "version": "v2",
      "updated": "2013-02-12T19:38:54.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "wide orbits",
      "giant planet",
      "brown dwarf",
      "wide-orbit companions",
      "disk fragmentation"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1051/0004-6361/201220601",
      "journal": "Astronomy and Astrophysics",
      "year": 2013,
      "month": "Apr",
      "volume": 552
    },
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1218120,
      "adsabs": "2013A&A...552A.129V"
    }
  }
}