{
  "id": "1705.07302",
  "version": "v1",
  "published": "2017-05-20T13:35:39.000Z",
  "updated": "2017-05-20T13:35:39.000Z",
  "title": "Rapid rotators revisited: absolute dimensions of KOI-13",
  "authors": [
    "Ian D. Howarth",
    "Giuseppe Morello"
  ],
  "comment": "Accepted in MNRAS",
  "doi": "10.1093/mnras/stx1260",
  "categories": [
    "astro-ph.SR",
    "astro-ph.EP"
  ],
  "abstract": "We analyse Kepler light-curves of the exoplanet KOI-13b transiting its moderately rapidly rotating (gravity-darkened) parent star. A physical model, with minimal ad hoc free parameters, reproduces the time-averaged light-curve at the ca. 10 parts per million level. We demonstrate that this Roche-model solution allows the absolute dimensions of the system to be determined from the star's projected equatorial rotation speed, v(e)sin(i), without any additional assumptions; we find a planetary radius 1.33+/-0.05 R(Jup), stellar polar radius 1.55+/-0.06 R(sun), combined mass M(*) + M(P) (\\simeq M*) = 1.47 +/- 0.17 M(sun), and distance d \\simeq 370+/-25 pc, where the errors are dominated by uncertainties in relative flux contribution of the visual-binary companion KOI-13B. The implied stellar rotation period is within ca. 5% of the non-orbital, 25.43-hr signal found in the Kepler photometry. We show that the model accurately reproduces independent tomographic observations, and yields an offset between orbital and stellar-rotation angular-momentum vectors of 60.25+/-0.05 degrees.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-05-20T13:35:39.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "absolute dimensions",
      "rapid rotators",
      "minimal ad hoc free parameters",
      "projected equatorial rotation",
      "accurately reproduces independent tomographic observations"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}