{
  "id": "2309.08386",
  "version": "v1",
  "published": "2023-09-15T13:25:56.000Z",
  "updated": "2023-09-15T13:25:56.000Z",
  "title": "Spectroscopic Searches for Evolutionary Orbital Period Changes in WR+OB Binaries: the case of V444 Cyg",
  "authors": [
    "I. Shaposhnikov",
    "A. Cherepashchuk",
    "A. Dodin",
    "K. Postnov"
  ],
  "comment": "6 pages, 5 figures, 3 tables, accepted for publication in MNRAS",
  "categories": [
    "astro-ph.SR",
    "astro-ph.HE"
  ],
  "abstract": "We present the results of new photometric and spectroscopic observations of WN5+O6 binary V444 Cyg and a detailed analysis of extant spectroscopy and photometry. Using elements of the spectroscopic orbit and assuming e = 0, i = 78{\\deg} we determined the masses and orbit sizes of the components of V444 Cyg M_O6 = 26.4 M_Sun, M_WN5 = 10.7 M_Sun, a_O6 = 10.6 R_Sun, a_WN5 = 26.1 R_Sun. Based on new and archival light curves and by applying the Hertzsprung method, we improved the photometrical estimate of secular increase rate of the orbital period in V444 Cyg dP/dt_ph = 0.119+-0.003 s/yr. From the comparison of the new and archival radial velocity curves of V444 Cyg we independently derived the secular orbital period change rate dP/dt_sp = 0.147+-0.032 s/yr, in agreement with the photometrical dP/dt_ph. The obtained secular increase rate of the binary orbital period dP/dt and the mean radii of the components enabled us to estimate the stellar wind mass-loss rate from WR star dM/dt_WN5 = -(6.0+-0.4)*10^-6 M_Sun/yr.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-09-15T13:25:56.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "evolutionary orbital period changes",
      "v444 cyg",
      "spectroscopic searches",
      "secular increase rate",
      "secular orbital period change rate"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}