{
  "id": "1601.02772",
  "version": "v1",
  "published": "2016-01-12T09:04:57.000Z",
  "updated": "2016-01-12T09:04:57.000Z",
  "title": "The magnificent past of RR Lyrae variables",
  "authors": [
    "Ennio Poretti",
    "Jean-Francois Le Borgne",
    "Alain Klotz",
    "Maurice Audejean",
    "Kenji Hirosawa"
  ],
  "comment": "Contributed paper to the Conference \"RRL2015 - High-Precision Studies of RR Lyrae stars\", held in Visegrad (Hungary), October 19-22, 2015. Proceedings to be published as the No. 105 issue of the Communications from the Konkoly Observatory of the Hungarian Academy of Sciences. This issue will be edited by L\\'aszl\\'o Szabados, R\\'obert Szab\\'o and Karen Kinemuchi",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "The history of the observations of RR Lyr variables started in the XIXth century, more than 120 years ago. The very long time baseline of available data combined with the short period of RR Lyrae variables offer an unique opportunity to look at their past as a treasure of valuable information. At this purpose, the amateur/professional association Groupe Europeen d'Observations Stellaires (GEOS) has built a database aimed to gather all the published maxima. We could study the period changes due to stellar evolution. Most of the 123 scrutinized RRab stars does not show any significant period variation. This reflects the fact that the rapid evolution is confined in short evolutionary phases. Notwithstanding this, we could put in evidence period increases in 27 stars and decreases in 21 ones. We also used the GEOS database to study the Blazhko effect of galactic RRab stars. The closed curves representing the Blazhko effect are constructed by plotting the magnitudes at maximum vs. the O-C values. We obtained a variegate family of Blazhko \"potatoes\". We could also reconstruct the changes in the pulsational and Blazhko periods of RR Lyr itself, resulted to be completely decoupled. Moreover, the amplitude of the Blazhko effect decreased so much to be hardly detectable by looking at the maxima collected in 2014 only. The effect seems to start again in the 2015 data.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-01-12T09:04:57.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "rr lyrae variables",
      "magnificent past",
      "blazhko effect",
      "association groupe europeen dobservations stellaires",
      "amateur/professional association groupe europeen dobservations"
    ],
    "tags": [
      "conference paper"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}