{
  "id": "1611.08409",
  "version": "v1",
  "published": "2016-11-25T10:41:14.000Z",
  "updated": "2016-11-25T10:41:14.000Z",
  "title": "Variability in the Milky Way: Contact binaries as diagnostic tools",
  "authors": [
    "Richard de Grijs",
    "Xiaodian Chen",
    "Licai Deng"
  ],
  "comment": "Invited talk; 5 pages, to appear in: The non-stable Universe: Energetic sources, activity phenomena and evolutionary processes, eds Mickaelian A., Harutyunian H., Nikoghosyan E., Byurakan (Armenia); ASP Conf. Ser",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "We used the 50 cm Binocular Network (50BiN) telescope at Delingha Station (Qinghai Province) of Purple Mountain Observatory (Chinese Academy of Sciences) to obtain simultaneous $V$- and $R$-band observations of the old open cluster NGC 188. Our aim was a search for populations of variable stars. We derived light-curve solutions for six W Ursae Majoris (W UMa) eclipsing-binary systems and estimated their orbital parameters. The resulting distance to the W UMas is independent of the physical characteristics of the host cluster. We next determined the current best period--luminosity relations for contact binaries (CBs; scatter $\\sigma < 0.10$ mag). We conclude that CBs can be used as distance tracers with better than 5\\% uncertainty. We apply our new relations to the 102 CBs in the Large Magellanic Cloud, which yields a distance modulus of $(m-M_V)_0=18.41\\pm0.20$ mag.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-11-25T10:41:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "contact binaries",
      "diagnostic tools",
      "milky way",
      "old open cluster ngc",
      "variability"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 5,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}