{
  "id": "2205.05815",
  "version": "v1",
  "published": "2022-05-12T00:43:30.000Z",
  "updated": "2022-05-12T00:43:30.000Z",
  "title": "Coronal and chromospheric emission in A-type stars",
  "authors": [
    "Hans Moritz Günther",
    "Carl Melis",
    "J. Robrade",
    "P. C. Schneider",
    "Scott J. Wolk",
    "Rakesh K. Yadav"
  ],
  "comment": "11 pages, 3 figures, accepted by AJ",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "Cool stars on the main sequence generate X-rays from coronal activity, powered by a convective dynamo. With increasing temperature, the convective envelope becomes smaller and X-ray emission fainter. We present Chandra/HRC-I observations of four single stars with early A spectral types. Only the coolest star of this sample, $\\tau^3$ Eri ($T_\\mathrm{eff}\\approx8\\,,000$ K), is detected with $\\log(L_X/L_\\mathrm{bol})=-7.6$ while the three hotter stars ($T_\\mathrm{eff}\\geq8\\,,000$ K), namely $\\delta$ Leo, $\\beta$ Leo, and $\\iota$ Cen, remain undetected with upper limits $\\log(L_X/L_\\mathrm{bol})<-8.4$. The drop in X-ray emission thus occurs in a narrow range of effective temperatures around $\\sim 8100$ K and matches the drop of activity in the C III and O VI transition region lines.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-05-12T00:43:30.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "a-type stars",
      "chromospheric emission",
      "main sequence generate x-rays",
      "vi transition region lines",
      "x-ray emission fainter"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}