{
  "id": "1503.06662",
  "version": "v1",
  "published": "2015-03-23T14:42:37.000Z",
  "updated": "2015-03-23T14:42:37.000Z",
  "title": "Magnetic field measurements of $ε$ Eridani from Zeeman broadening",
  "authors": [
    "L. T. Lehmann",
    "A. Künstler",
    "T. A. Carroll",
    "K. G. Strassmeier"
  ],
  "doi": "10.1002/asna.201412162",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "We present new magnetic field measurements of the K2 main-sequence star $\\epsilon$ Eridani based on principal components analysis (PCA) line-profile reconstructions. The aim of this paper is to quantify the surface-averaged magnetic field and search for possible variations. A total of 338 optical echelle spectra from our robotic telescope facility STELLA with a spectral resolution of 55,000 were available for analysis. This time-series was used to search for the small line-profile variations due to a surface magnetic field with the help of a PCA. Evidence for a spatial and temporal inhomogeneous magnetic field distribution is presented. The mean, surface averaged, magnetic field strength was found to be $\\langle B \\rangle = 186 \\pm 47\\,\\mathrm{G}$ in good agreement with previous Zeeman-broadening measurements. Clear short-term variations of the surface averaged magnetic field of up to few tens Gauss were detected together with evidence for a three-year cycle in the surface-averaged magnetic field of $\\epsilon$ Eridani.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-03-23T14:42:37.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "magnetic field measurements",
      "zeeman broadening",
      "surface-averaged magnetic field",
      "temporal inhomogeneous magnetic field distribution",
      "robotic telescope facility stella"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "journal": "Astronomische Nachrichten",
      "year": 2015,
      "month": "Apr",
      "volume": 336,
      "number": 3,
      "pages": 258
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015AN....336..258L"
    }
  }
}