{
  "id": "1808.01251",
  "version": "v1",
  "published": "2018-08-03T16:36:20.000Z",
  "updated": "2018-08-03T16:36:20.000Z",
  "title": "Periodic Variability of the Barium Central Star of the Planetary Nebula Abell 70",
  "authors": [
    "Howard E. Bond",
    "Robin Ciardullo"
  ],
  "comment": "Accepted by Research Notes of the AAS. Published version will be slightly shorter due to word-count limitations",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "Abell 70 is a planetary nebula (PN) whose nucleus at optical wavelengths is a G8 star with enhanced carbon and s-process abundances--a \"barium star.\" The cool star is a binary companion of the true, hot central star. In several other members of this rare class, the cool star is known to rotate with a period of only a few days. This is attributed to a spin-up that occurred due to accretion from the wind of the central star during its post-AGB PN ejection; this also accounts for the unusual chemical composition of the companion's photosphere. We obtained photometry of the central star of Abell 70 on 104 nights in 2010-11, and find a periodic 2.061-day variation, but with a variable amplitude--indicating that the variability is due to starspots on a chromospherically active star. Abell 70 thus joins other members of this class in having a rapidly rotating and chemically peculiar late-type companion of the hot central star.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-08-03T16:36:20.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "barium central star",
      "planetary nebula abell",
      "periodic variability",
      "hot central star",
      "cool star"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}