{
  "@type": "dcat:Dataset",
  "accessLevel": "public",
  "bureauCode": [
    "026:00"
  ],
  "contactPoint": {
    "@type": "vcard:Contact",
    "fn": "HEASARC Help Desk",
    "hasEmail": "mailto:andrew.ptak@nasa.gov"
  },
  "description": "This catalog presents X-ray data for all entries in the Third Catalogue of Nearby Stars (CNS3: Gliese and Jahreiss, 1991, ADC/CDS Cat. <V/70>) that have been detected as X-ray sources in the ROSAT All-Sky Survey (RASS). The catalog contains 1252 entries, yielding an average detection rate of 32.9 percent of the 3802 CNS3 stars. In addition to count rates, source detection parameters, X-ray hardness ratios, and X-ray fluxes, X-ray luminosities derived from Hipparcos parallaxes are also listed. For a star to have been considered by the authors to have been detected as an X-ray source in the RASS, an X-ray source with an existence likelihood of 7 or more (equivalent to a source existence probablity of 99.9 percent or more) had to lie within 90 arcseconds of its 1990 epoch CNS3 position. The choice of this cut-off radius was based on a Monte Carlo simulation of about the same number of random positions that were used as input positions. At an offset of 90 arcseconds between the optical and X-ray positions the probability that the X-ray source is attributable to the star and not to a unrelated background object is 50 percent; this probability increases very rapidly for smaller values of the offset, notice. This database was created in June 1999 based on tables provided by the ADC/CDS data centers supplemented by additional tabular material provided to the HEASARC by the author Dr. M. Huensch. This is a service provided by NASA HEASARC .",
  "distribution": [
    {
      "@type": "dcat:Distribution",
      "downloadURL": "https://heasarc.gsfc.nasa.gov/W3Browse/all/rasscns3.html",
      "format": "HTML",
      "mediaType": "text/html"
    },
    {
      "@type": "dcat:Distribution",
      "downloadURL": "https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=rasscns3&",
      "format": "BIN",
      "mediaType": "application/octet-stream"
    }
  ],
  "identifier": "ivo://nasa.heasarc/rasscns3",
  "keyword": [
    "__"
  ],
  "landingPage": "ivo://nasa.heasarc/rasscns3",
  "license": "https://www.usa.gov/government-works",
  "modified": "2026-09-21",
  "programCode": [
    "026:000"
  ],
  "publisher": {
    "@type": "org:Organization",
    "name": "High Energy Astrophysics Science Archive Research Center"
  },
  "theme": [
    "Astrophysics"
  ],
  "title": "ROSAT All-Sky Survey: Nearby Stars"
}