{
  "id": "1409.1351",
  "version": "v1",
  "published": "2014-09-04T08:09:36.000Z",
  "updated": "2014-09-04T08:09:36.000Z",
  "title": "Improving the surface-brightness color relation for early-type stars using optical interferometry",
  "authors": [
    "M. Challouf",
    "N. Nardetto",
    "D. Mourard",
    "D. Graczyk",
    "H. Aroui",
    "O. Chesneau",
    "O. Delaa",
    "G. Pietrzyński",
    "W. Gieren",
    "R. Ligi",
    "A. Meilland",
    "K. Perraut",
    "I. Tallon-Bosc",
    "H. McAlister",
    "T. ten Brummelaar",
    "J. Sturmann",
    "L. Sturmann",
    "N. Turner",
    "C. Farrington",
    "N. Vargas",
    "N. Scott"
  ],
  "comment": "13 pages, 5 figures, accepted for publication in A&A",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "The aim of this work is to improve the SBC relation for early-type stars in the $-1 \\leq V-K \\leq 0$ color domain, using optical interferometry. Observations of eight B- and A-type stars were secured with the VEGA/CHARA instrument in the visible. The derived uniform disc angular diameters were converted into limb darkened angular diameters and included in a larger sample of twenty four stars, already observed by interferometry, in order to derive a revised empirical relation for O, B, A spectral type stars with a V-K color index ranging from -1 to 0. We also take the opportunity to check the consistency of the SBC relation up to $V-K \\simeq 4$ using 100 additional measurements. We determined the uniform disc angular diameter for the eight following stars: $\\gamma$ Ori, $\\zeta$ Per, $8$ Cyg, $\\iota$ Her, $\\lambda$ Aql, $\\zeta$ Peg, $\\gamma$ Lyr and $\\delta$ Cyg with V-K color ranging from -0.70 to 0.02 and typical precision of about $1.5\\%$. Using our total sample of 132 stars with $V-K$ colors index ranging from about $-1$ to $4$, we provide a revised SBC relation. For late-type stars ($0 \\leq V-K \\leq 4$), the results are consistent with previous studies. For early-type stars ($-1 \\leq V-K \\leq 0$), our new VEGA/CHARA measurements combined with a careful selection of the stars (rejecting stars with environment or stars with a strong variability), allows us to reach an unprecedented precision of about 0.16 magnitude or $\\simeq 7\\%$ in term of angular diameter.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-09-04T08:09:36.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "early-type stars",
      "surface-brightness color relation",
      "optical interferometry",
      "sbc relation",
      "derived uniform disc angular diameters"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1051/0004-6361/201423772",
      "journal": "Astronomy and Astrophysics",
      "year": 2014,
      "month": "Oct",
      "volume": 570
    },
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014A&A...570A.104C"
    }
  }
}