{
  "id": "1609.06611",
  "version": "v1",
  "published": "2016-09-21T15:59:22.000Z",
  "updated": "2016-09-21T15:59:22.000Z",
  "title": "A Search for Mass Loss on the Cepheid Instability Strip using HI 21-cm Line Observations",
  "authors": [
    "L. D. Matthews",
    "M. Marengo",
    "N. R. Evans"
  ],
  "comment": "Accepted to AJ; 16 pages",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "We present the results of a search for HI 21-cm line emission from the circumstellar environments of four Galactic Cepheids (RS Pup, X Cyg, $\\zeta$ Gem, and T Mon) based on observations with the Karl G. Jansky Very Large Array. The observations were aimed at detecting gas associated with previous or ongoing mass loss. Near the long-period Cepheid T Mon, we report the detection of a partial shell-like structure whose properties appear consistent with originating from an earlier epoch of Cepheid mass loss. At the distance of T Mon, the nebula would have a mass (HI+He) of $\\sim0.5M_{\\odot}$, or $\\sim$6\\% of the stellar mass. Assuming that one-third of the nebular mass comprises swept-up interstellar gas, we estimate an implied mass-loss rate of ${\\dot M}\\sim (0.6-2)\\times10^{-5} M_{\\odot}$ yr$^{-1}$. No clear signatures of circumstellar emission were found toward $\\zeta$ Gem, RS Pup, or X Cyg, although in each case, line-of-sight confusion compromised portions of the spectral band. For the undetected stars, we derive model-dependent $3\\sigma$ upper limits on the mass-loss rates, averaged over their lifetimes on the instability strip, of $<(0.3-6)\\times10^{-6} M_{\\odot}$ yr$^{-1}$ and estimate the total amount of mass lost to be less than a few per cent of the stellar mass.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-09-21T15:59:22.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "mass loss",
      "cepheid instability strip",
      "line observations",
      "mass comprises swept-up interstellar gas",
      "nebular mass comprises swept-up interstellar"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}