{
  "id": "2008.05834",
  "version": "v1",
  "published": "2020-08-13T11:44:19.000Z",
  "updated": "2020-08-13T11:44:19.000Z",
  "title": "The extreme colliding-wind system Apep: resolved imagery of the central binary and dust plume in the infrared",
  "authors": [
    "Y. Han",
    "P. G. Tuthill",
    "R. M. Lau",
    "A. Soulain",
    "J. R. Callingham",
    "P. M. Williams",
    "P. A. Crowther",
    "B. J. S. Pope",
    "B. Marcote"
  ],
  "comment": "This article has been accepted for publication in the Monthly Notices of the Royal Astronomical Society. 17 pages, 9 figures, 6 tables",
  "categories": [
    "astro-ph.SR",
    "astro-ph.HE",
    "astro-ph.IM"
  ],
  "abstract": "The recent discovery of a spectacular dust plume in the system 2XMM J160050.7-514245 (referred to as \"Apep\") suggested a physical origin in a colliding-wind binary by way of the \"Pinwheel\" mechanism. Observational data pointed to a hierarchical triple-star system, however several extreme and unexpected physical properties seem to defy the established physics of such objects. Most notably, a stark discrepancy was found in the observed outflow speed of the gas as measured spectroscopically in the line-of-sight direction compared to the proper motion expansion of the dust in the sky plane. This enigmatic behaviour arises at the wind base within the central Wolf-Rayet binary: a system that has so far remained spatially unresolved. Here we present an updated proper motion study deriving the expansion speed of Apep's dust plume over a two-year baseline that is four times slower than the spectroscopic wind speed, confirming and strengthening the previous finding. We also present the results from high-angular-resolution near-infrared imaging studies of the heart of the system, revealing a close binary with properties matching a Wolf-Rayet colliding-wind system. Based on these new observational constraints, an improved geometric model is presented yielding a close match to the data, constraining the orbital parameters of the Wolf-Rayet binary and lending further support to the anisotropic wind model.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-08-13T11:44:19.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "extreme colliding-wind system apep",
      "central binary",
      "resolved imagery",
      "proper motion study deriving",
      "wolf-rayet binary"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}