{
  "id": "2307.10394",
  "version": "v1",
  "published": "2023-07-19T18:04:55.000Z",
  "updated": "2023-07-19T18:04:55.000Z",
  "title": "Refining the Stellar Parameters of $τ$ Ceti: a Pole-on Solar Analog",
  "authors": [
    "Maria Korolik",
    "Rachael M. Roettenbacher",
    "Debra A. Fischer",
    "Stephen R. Kane",
    "Jean M. Perkins",
    "John D. Monnier",
    "Claire L. Davies",
    "Stefan Kraus",
    "Jean-Baptiste Le Bouquin",
    "Narsireddy Anugu",
    "Tyler Gardner",
    "Cyprien Lanthermann",
    "Gail H. Schaefer",
    "Benjamin Setterholm",
    "John M. Brewer",
    "Joe Llama",
    "Lily L. Zhao",
    "Andrew E. Szymkowiak",
    "Gregory W. Henry"
  ],
  "comment": "14 pages, 3 figures, 4 tables, 1 appendix, accepted for publication to AJ",
  "categories": [
    "astro-ph.SR",
    "astro-ph.EP"
  ],
  "abstract": "To accurately characterize the planets a star may be hosting, stellar parameters must first be well-determined. $\\tau$ Ceti is a nearby solar analog and often a target for exoplanet searches. Uncertainties in the observed rotational velocities have made constraining $\\tau$ Ceti's inclination difficult. For planet candidates from radial velocity (RV) observations, this leads to substantial uncertainties in the planetary masses, as only the minimum mass ($m \\sin i$) can be constrained with RV. In this paper, we used new long-baseline optical interferometric data from the CHARA Array with the MIRC-X beam combiner and extreme precision spectroscopic data from the Lowell Discovery Telescope with EXPRES to improve constraints on the stellar parameters of $\\tau$ Ceti. Additional archival data were obtained from a Tennessee State University Automatic Photometric Telescope and the Mount Wilson Observatory HK project. These new and archival data sets led to improved stellar parameter determinations, including a limb-darkened angular diameter of $2.019 \\pm 0.012$ mas and rotation period of $46 \\pm 4$ days. By combining parameters from our data sets, we obtained an estimate for the stellar inclination of $7\\pm7^\\circ$. This nearly-pole-on orientation has implications for the previously-reported exoplanets. An analysis of the system dynamics suggests that the planetary architecture described by Feng et al. (2017) may not retain long-term stability for low orbital inclinations. Additionally, the inclination of $\\tau$ Ceti reveals a misalignment between the inclinations of the stellar rotation axis and the previously-measured debris disk rotation axis ($i_\\mathrm{disk} = 35 \\pm 10^\\circ$).",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-07-19T18:04:55.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "stellar parameter",
      "pole-on solar analog",
      "wilson observatory hk project",
      "university automatic photometric telescope",
      "debris disk rotation axis"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}