{
  "id": "1106.1152",
  "version": "v2",
  "published": "2011-06-06T19:00:41.000Z",
  "updated": "2011-07-22T23:59:32.000Z",
  "title": "55 Cancri: Stellar Astrophysical Parameters, a Planet in the Habitable Zone, and Implications for the Radius of a Transiting Super-Earth",
  "authors": [
    "Kaspar von Braun",
    "Tabetha S. Boyajian",
    "Theo A. ten Brummelaar",
    "Stephen R. Kane",
    "Gerard T. van Belle",
    "David R. Ciardi",
    "Sean N. Raymond",
    "Mercedes Lopez-Morales",
    "Harold A. McAlister",
    "Gail Schaefer",
    "Stephen T. Ridgway",
    "Laszlo Sturmann",
    "Judit Sturmann",
    "Russel White",
    "Nils H. Turner",
    "Chris Farrington",
    "P. J. Goldfinger"
  ],
  "comment": "revised version after incorporating referee's comments and suggestions by members of the astronomical community; 7 pages, 4 figures, 2 tables; accepted for publication in ApJ",
  "categories": [
    "astro-ph.EP",
    "astro-ph.SR"
  ],
  "abstract": "The bright star 55 Cancri is known to host five planets, including a transiting super-Earth. The study presented here yields directly determined values for 55 Cnc's stellar astrophysical parameters based on improved interferometry: $R=0.943 \\pm 0.010 R_{\\odot}$, $T_{\\rm EFF} = 5196 \\pm 24$ K. We use isochrone fitting to determine 55 Cnc's age to be 10.2 $\\pm$ 2.5 Gyr, implying a stellar mass of $0.905 \\pm 0.015 M_{\\odot}$. Our analysis of the location and extent of the system's habitable zone (0.67--1.32 AU) shows that planet f, with period $\\sim$ 260 days and $M \\sin i = 0.155 M_{Jupiter}$, spends the majority of the duration of its elliptical orbit in the circumstellar habitable zone. Though planet f is too massive to harbor liquid water on any planetary surface, we elaborate on the potential of alternative low-mass objects in planet f's vicinity: a large moon, and a low-mass planet on a dynamically stable orbit within the habitable zone. Finally, our direct value for 55 Cancri's stellar radius allows for a model-independent calculation of the physical diameter of the transiting super-Earth 55 Cnc e ($\\sim 2.05 \\pm 0.15 R_{\\earth}$), which, depending on the planetary mass assumed, implies a bulk density of 0.76 $\\rho_{\\earth}$ or 1.07 $\\rho_{\\earth}$.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2011-07-22T23:59:32.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "habitable zone",
      "transiting super-earth",
      "implications",
      "cancris stellar radius",
      "cncs stellar astrophysical parameters"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/740/1/49",
      "journal": "The Astrophysical Journal",
      "year": 2011,
      "month": "Oct",
      "volume": 740,
      "number": 1,
      "pages": 49
    },
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 913008,
      "adsabs": "2011ApJ...740...49V"
    }
  }
}