{
  "id": "2106.08328",
  "version": "v1",
  "published": "2021-06-15T18:00:00.000Z",
  "updated": "2021-06-15T18:00:00.000Z",
  "title": "Eclipsing Binaries Found by the EREBOS Project: Gaia DR2 6097540197980557440 -- A Deeply Eclipsing sdB+dM System",
  "authors": [
    "Kyle A. Corcoran",
    "Brad N. Barlow",
    "Veronika Schaffenroth",
    "Uli Heber",
    "Stephen Walser",
    "Andreas Irgang"
  ],
  "comment": "15 pages, 9 figures, accepted for publication by ApJ",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "We present time-series spectroscopy and photometry of Gaia DR2 6097540197980557440, a new deeply-eclipsing hot subdwarf B (sdB) + M dwarf (dM) binary. We discovered this object during the course of the Eclipsing Reflection Effect Binaries from Optical Surveys (EREBOS) project, which aims to find new eclipsing sdB+dM binaries (HW Vir systems) and increase the small sample of studied systems. In addition to the primary eclipse, which is in excess of $\\sim$5 magnitudes in the optical, the light curve also shows features typical for other HW Vir binaries such as a secondary eclipse and strong reflection effect from the irradiated, cool companion. The orbital period is 0.127037 d ($\\sim$3 hr), falling right at the peak of the orbital period distribution of known HW Vir systems. Analysis of our time-series spectroscopy yields a radial velocity semi-amplitude of $K_{\\rm sdB}=100.0\\pm2.0\\,{\\rm km\\,s}^{-1}$, which is amongst the fastest line-of-sight velocities found to date for an HW Vir binary. State-of-the-art atmospheric models that account for deviations from local thermodynamic equilibrium are used to determine the atmospheric parameters of the sdB. Although we cannot claim a unique light curve modeling solution, the best-fitting model has an sdB mass of $M_{\\rm sdB} = 0.47\\pm0.03\\,M_{\\odot}$ and a companion mass of $M_{\\rm dM} = 0.18\\pm0.01\\,M_{\\odot}$. The radius of the companion appears to be inflated relative to theoretical mass-radius relationships, consistent with other known HW Vir binaries. Additionally, the M dwarf is one of the most massive found to date amongst this type of binary.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-06-15T18:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "gaia dr2",
      "hw vir binary",
      "erebos project",
      "eclipsing binaries",
      "light curve modeling solution"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 15,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}