{
  "id": "I/311",
  "title_cds": "Hipparcos, the New Reduction",
  "title_create": "van Leeuwen, 2007",
  "year": "2007",
  "author": "van Leeuwen F.",
  "title_pub": " Hipparcos, the new Reduction of the Raw data",
  "first_author": "van Leeuwen F.",
  "bibcode": [
    "2007A&A...474..653V"
  ],
  "ref_biblio": [
    "<Astron. Astrophys. 474, 653 (2007)>"
  ],
  "keyword_cds": [
    "Positional data",
    "Proper motions",
    "Parallaxes, trigonometric",
    "Photometry",
    "Fundamental catalog"
  ],
  "keyword_pub": "space vehicles: instruments - methods: data analysis  - catalogs - astrometry  - instrumentation: miscellaneous",
  "mission": "Hipparcos",
  "abstract": [
    "A new reduction of the astrometric data as produced by the Hipparcos",
    "mission has been published, claiming accuracies for nearly all stars",
    "brighter than magnitude Hp=8 to be better, by up to a factor 4, than",
    "in the original catalogue.",
    "",
    "The new Hipparcos astrometric catalogue is checked for the quality of",
    "the data and the consistency of the formal errors as well as the",
    "possible presence of error correlations. The differences with the",
    "earlier publication are explained.",
    "",
    "Methods. The internal errors are followed through the reduction",
    "process, and the external errors are investigated on the basis of a",
    "comparison with radio observations of a small selection of stars, and",
    "the distribution of negative parallaxes. Error correlation levels are",
    "investigated and the reduction by more than a factor 10 as obtained in",
    "the new catalogue is explained.",
    "",
    "Results. The formal errors on the parallaxes for the new catalogue are",
    "confirmed. The presence of a small amount of additional noise, though",
    "unlikely, cannot be ruled out.",
    "",
    "Conclusions. The new reduction of the Hipparcos astrometric data",
    "provides an improvement by a factor 2.2 in the total weight compared",
    "to the catalogue published in 1997, and provides much improved data",
    "for a wide range of studies on stellar luminosities and local galactic",
    "kinematics.",
    "",
    "Notice:",
    "The files included are slightly different from the ones published in",
    "the book, as an error that sometimes affected the goodness of fit",
    "value for the solution was corrected. The first version of these files",
    "(between June and 15 September 2008) also contained errors corrected",
    "after this date."
  ],
  "curator": "Francois Ochsenbein [CDS]",
  "history": [
    "* 09-Jun-2008: Original version (with errors)",
    "* 16-Sep-2008: new files from author"
  ],
  "see_also": [
    "I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)"
  ],
  "ack": "Floor van Leeuwen, Institute of Astronomy, Cambridge University Cambrisge, UK",
  "tables": [
    {
      "name": "hip2.dat",
      "desc": "The Astrometric Catalogue"
    },
    {
      "name": "hip7p.dat",
      "desc": "Seven-parameter solutions"
    },
    {
      "name": "hip9p.dat",
      "desc": "Nine-parameter solutions"
    },
    {
      "name": "hipvim.dat",
      "desc": "*Variability-induced (VIM) solutions"
    }
  ],
  "archive_date_creation": "07-Jul-2008",
  "catid": 1311,
  "vizier_date_update": "22-Dec-2017",
  "xmatch": "I/311/hip2",
  "doi_pub": [
    "10.1051/0004-6361:20078357"
  ],
  "alias": "HIP2",
  "type": [
    "OC"
  ],
  "records": "117955 stars",
  "archive_date_update": "08-Aug-2018",
  "uat": [
    "Astrometry",
    "Proper motions",
    "Optical astronomy",
    "Trigonometric parallax",
    "Photometry",
    "Optical observation",
    "Catalogs"
  ],
  "ip_addr": "216.73.216.17",
  "data_access": "v-f"
}