{
  "id": "1408.5596",
  "version": "v1",
  "published": "2014-08-24T11:46:29.000Z",
  "updated": "2014-08-24T11:46:29.000Z",
  "title": "The Role for the Inner Disk in Mass Accretion to the Star in the Early Phase of Star Formation",
  "authors": [
    "Takuya Ohtani",
    "Shigeo S. Kimura",
    "Toru Tsuribe",
    "Eduard I. Vorobyov"
  ],
  "comment": "20 pages, 7 figures, accepted for publication in PASJ",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "A physical mechanism that drives FU Orionis-type outbursts is reconsidered. We study the effect of inner part of a circumstellar disk covering a region from near the central star to the radius of approximately $5$ AU (hereafter, the inner disk). Using the fluctuated mass accretion rate onto the inner disk $\\dot{M}_{\\rm out}$, we consider the viscous evolution of the inner disk and the time variability of the mass accretion rate onto the central star $\\dot{M}_{\\rm in}$ by means of numerical calculation of an unsteady viscous accretion disk in a one-dimensional axisymmetric model. First, we calculate the evolution of the inner disk assuming an oscillating $\\dot{M}_{\\rm out}$. It is shown that the time variability of $\\dot{M}_{\\rm in}$ does not coincide with $\\dot{M}_{\\rm out}$ due to viscous diffusion. Second, we investigate the properties of spontaneous outbursts with temporally constant $\\dot{M}_{\\rm out}$. Outburst occur only in a limited range of mass accretion rates onto the inner disk $10^{-10}<\\dot{M}_{\\rm out}< 3\\times 10^{-6}~{\\rm M}_{\\odot} {\\rm yr}^{-1}$ due to gravo-magneto limit cycle (GML). Finally, we discuss the case with a combination of episodic $\\dot{M}_{\\rm out}$ and accretion outbursts cause by the GML in the inner disk. The GML can drive accretion outbursts onto the star even for the case of fluctuating $\\dot{M}_{\\rm out}$, although fluctuations of $\\dot{M}$ decay during transmitting the inner disk inwards. We newly identified two modes of outburst which are spontaneous one and stimulated one. In a stimulated mode of outburst, $\\dot{M}_{\\rm out}$ does appear directly in $\\dot{M}_{\\rm in}$ (the latter defining the stellar accretion luminosity). In a spontaneous mode of outburst, $\\dot{M}_{\\rm out}$ appears as the interval between outbursts.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-08-24T11:46:29.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "inner disk",
      "mass accretion rate",
      "star formation",
      "early phase",
      "time variability"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1093/pasj/psu098",
      "journal": "Publications of the Astronomical Society of Japan",
      "year": 2014,
      "month": "Dec",
      "volume": 66,
      "number": 6,
      "pages": 112
    },
    "note": {
      "typesetting": "TeX",
      "pages": 20,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014PASJ...66..112O"
    }
  }
}