{
  "id": "1406.1437",
  "version": "v1",
  "published": "2014-06-05T16:36:39.000Z",
  "updated": "2014-06-05T16:36:39.000Z",
  "title": "Episodic Mass Loss from the Hydrogen-Deficient Central Star of the Planetary Nebula Longmore 4",
  "authors": [
    "Howard E. Bond"
  ],
  "comment": "Accepted by Astronomical Journal",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "A spectacular transient mass-loss episode from the extremely hot, hydrogen-deficient central star of the planetary nebula (PN) Longmore 4 was discovered in 1992 by Werner et al. During that event, the star temporarily changed from its normal PG 1159 spectrum to that of an emission-line low-luminosity early-type Wolf-Rayet [WCE] star. After a few days, Lo 4 reverted to its normal, predominantly absorption-line PG 1159 type. To determine whether such events recur, and if so how often, I monitored the optical spectrum of Lo 4 from early 2003 to early 2012. Out of 81 spectra taken at random dates, four of them revealed mass-loss outbursts similar to that seen in 1992. This indicates that the episodes recur approximately every 100 days (if the recurrence rate has been approximately constant and the duration of a typical episode is ~5 days), and that the star is in a high-mass-loss state about 5% of the time. Since the enhanced stellar wind is hydrogen-deficient, it arises from the photosphere and is unlikely to be related to phenomena such as a binary or planetary companion or infalling dust. I speculate on plausible mechanisms for these unique outbursts, including the possibility that they are related to the non-radial GW Vir-type pulsations exhibited by Lo 4. The central star of the PN NGC 246 has stellar parameters similar to those of Lo 4, and it is also a GW Vir-type pulsator with similar pulsation periods. I obtained 167 spectra of NGC 246 between 2003 and 2011, but no mass ejections were found.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-06-05T16:36:39.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hydrogen-deficient central star",
      "episodic mass loss",
      "planetary nebula longmore",
      "emission-line low-luminosity early-type wolf-rayet",
      "spectacular transient mass-loss episode"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-6256/148/3/44",
      "journal": "The Astronomical Journal",
      "year": 2014,
      "month": "Sep",
      "volume": 148,
      "number": 3,
      "pages": 44
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014AJ....148...44B"
    }
  }
}