{
  "id": "2206.13339",
  "version": "v1",
  "published": "2022-06-27T14:41:26.000Z",
  "updated": "2022-06-27T14:41:26.000Z",
  "title": "FAUST VI. VLA 1623--2417 B: a new laboratory for astrochemistry around protostars on 50 au scale",
  "authors": [
    "C. Codella",
    "A. López-Sepulcre",
    "S. Ohashi",
    "C. J. Chandler",
    "M. De Simone",
    "L. Podio",
    "C. Ceccarelli",
    "N. Sakai",
    "F. Alves",
    "A. Durán",
    "D. Fedele",
    "L. Loinard",
    "S. Mercimek",
    "N. Murillo",
    "E. Bianchi",
    "M. Bouvier",
    "G. Busquet",
    "P. Caselli",
    "F. Dulieu",
    "S. Feng",
    "T. Hanawa",
    "D. Johnstone",
    "B. Lefloch",
    "L. T. Maud",
    "G. Moellenbrock",
    "Y. Oya",
    "B. Svoboda",
    "S. Yamamoto"
  ],
  "comment": "MNRAS, in press",
  "categories": [
    "astro-ph.GA",
    "astro-ph.SR"
  ],
  "abstract": "The ALMA interferometer, with its unprecedented combination of high-sensitivity and high-angular resolution, allows for (sub-)mm wavelength mapping of protostellar systems at Solar System scales. Astrochemistry has benefited from imaging interstellar complex organic molecules in these jet-disk systems. Here we report the first detection of methanol (CH3OH) and methyl formate (HCOOCH3) emission towards the triple protostellar system VLA1623-2417 A1+A2+B, obtained in the context of the ALMA Large Program FAUST. Compact methanol emission is detected in lines from Eu = 45 K up to 61 K and 537 K towards components A1 and B, respectively. LVG analysis of the CH3OH lines towards VLA1623-2417 B indicates a size of 0.11-0.34 arcsec (14-45 au), a column density N(CH3OH) = 10^16-10^17 cm-2, kinetic temperature > 170 K, and volume density > 10^8 cm-3. An LTE approach is used for VLA1623-2417 A1, given the limited Eu range, and yields Trot < 135 K. The methanol emission around both VLA1623-2417 A1 and B shows velocity gradients along the main axis of each disk. Although the axial geometry of the two disks is similar, the observed velocity gradients are reversed. The CH3OH spectra from B shows two broad (4-5 km s-1) peaks, which are red- and blue-shifted by about 6-7 km s-1 from the systemic velocity. Assuming a chemically enriched ring within the accretion disk, close to the centrifugal barrier, its radius is calculated to be 33 au. The methanol spectra towards A1 are somewhat narrower (about 4 km s-1), implying a radius of 12-24 au.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-06-27T14:41:26.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "au scale",
      "faust vi",
      "astrochemistry",
      "laboratory",
      "velocity gradients"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}