{
  "id": "1805.04547",
  "version": "v1",
  "published": "2018-05-11T18:30:46.000Z",
  "updated": "2018-05-11T18:30:46.000Z",
  "title": "Photometric variability of TW~Hya from seconds to years as seen from space and the ground in 2013-2017",
  "authors": [
    "M. Siwak",
    "W. Ogloza",
    "A. F. J. Moffat",
    "J. M. Matthews",
    "S. M. Rucinski",
    "T. Kallinger",
    "R. Kuschnig",
    "C. Cameron",
    "W. W. Weiss",
    "J. F. Rowe",
    "D. B. Guenther",
    "D. Sasselov"
  ],
  "comment": "Accepted by MNRAS",
  "doi": "10.1093/mnras/sty1220",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "This is the final photometric study of TW Hya based on new MOST satellite observations. During 2014 and 2017 the light curves showed stable 3.75 and 3.69 d quasi-periodic oscillations, respectively. Both values appear to be closely related with the stellar rotation period, as they might be created by changing visibility of a hot-spot formed near the magnetic pole directed towards the observer. These major light variations were superimposed on a chaotic, flaring-type activity caused by hot-spots resulting from unstable accretion - a situation reminiscent of that in 2011, when TW Hya showed signs of a moderately stable accretion state. In 2015 only drifting quasi-periods were observed, similar to those present in 2008-2009 data and typical for magnetised stars accreting in a strongly unstable regime. A rich set of multi-colour data was obtained during 2013-2017 with the primary aim to characterize the basic spectral properties of the mysterious occultations in TW Hya. Although several possible occultation-like events were identified, they are not as well defined as in the 2011 MOST data. The new ground-based and MOST data show a dozen previously unnoticed flares, as well as small-amplitude, 11 min - 3 hr brightness variations, associated with 'accretion bursts'. It is not excluded that the shortest 11-15 min variations could also be caused by thermal instability oscillations in an accretion shock.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-05-11T18:30:46.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "photometric variability",
      "final photometric study",
      "thermal instability oscillations",
      "tw hya showed signs",
      "stellar rotation period"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}