{
  "id": "2010.05392",
  "version": "v1",
  "published": "2020-10-12T01:39:22.000Z",
  "updated": "2020-10-12T01:39:22.000Z",
  "title": "Magnetically regulated disk-formation in the inner 100 au region of the Class 0 young stellar object OMC-3/MMS~6 resolved by JVLA and ALMA",
  "authors": [
    "Hauyu Baobab Liu"
  ],
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "We have carried out polarization calibration for archival JVLA ($\\sim$9 mm) full polarization observations towards the Class 0 young stellar object (YSO) OMC-3/MMS 6 (also known as HOPS-87), and then compared with the archival ALMA 1.2 mm observations. We found that the innermost $\\sim$100 au region of OMC-3/MMS 6 is likely very optically thick (e.g., $\\tau\\gg$1) at $\\sim$1 mm wavelength such that the dominant polarization mechanism is dichroic extinction. It is marginally optically thin (e.g., $\\tau\\lesssim$1) at $\\sim$9 mm wavelength such that the JVLA observations can directly probe the linearly polarized emission from non-spherical dust. Assuming that the projected long axis of dust grains is aligned perpendicular to magnetic field (B-field) lines, we propose that the overall B-field topology resembles an hourglass shape, while this \"hourglass\" appears $\\sim$40$^{\\circ}$ inclined with respect to the previously reported outflow axis. The geometry of this system is consistent with a magnetically regulated dense (pseudo-)disk. Based on the observed 29.45 GHz flux density and assuming a dust absorption opacity $\\kappa^{abs}_{29.45\\,GHz}=$0.0096 cm$^{2} $g$^{-1}$, the derived overall dust mass within a $\\sim$43 au radius is $\\sim$14000 $M_{\\oplus}$. From this case study, it appears to us that some previous 9 mm surveys towards Class 0/I YSOs might have systematically underestimated dust masses by one order of magnitude, owing to that they assumed the too high dust absorption opacity ($\\sim$0.1 cm$^{2}$ g$^{-1}$) for $\\sim$9 mm wavelengths but without self-consistently considering the dust scattering opacity.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-10-12T01:39:22.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "young stellar object",
      "magnetically regulated disk-formation",
      "au region",
      "mm wavelength",
      "high dust absorption opacity"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}