{
  "id": "0904.1747",
  "version": "v1",
  "published": "2009-04-10T20:05:48.000Z",
  "updated": "2009-04-10T20:05:48.000Z",
  "title": "Multiple and changing cycles of active stars II. Results",
  "authors": [
    "K. Oláh",
    "Z. Kolláth",
    "T. Granzer",
    "K. G. Strassmeier",
    "A. F. Lanza",
    "S. Järvinen",
    "H. Korhonen",
    "S. L. Baliunas",
    "W. Soon",
    "S. Messina",
    "G. Cutispoto"
  ],
  "comment": "Accepted to Astronomy and Astrophysics",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "We study the time variations of the cycles of 20 active stars based on decades-long photometric or spectroscopic observations. A method of time-frequency analysis, as discussed in a companion paper, is applied to the data. Fifteen stars definitely show multiple cycles; the records of the rest are too short to verify a timescale for a second cycle. The cycles typically show systematic changes. For three stars, we found two cycles in each of them that are not harmonics, and which vary in parallel, indicating that a common physical mechanism arising from a dynamo construct. The positive relation between the rotational and cycle periods is confirmed for the inhomogeneous set of active stars. Stellar activity cycles are generally multiple and variable.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2009-04-10T20:05:48.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "active stars",
      "changing cycles",
      "stellar activity cycles",
      "time variations",
      "cycle periods"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1051/0004-6361/200811304",
      "journal": "Astronomy and Astrophysics",
      "year": 2009,
      "month": "Jul",
      "volume": 501,
      "number": 2,
      "pages": 703
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 817782,
      "adsabs": "2009A&A...501..703O"
    }
  }
}