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    <title>
       Trapezium Multiple Systems (Salukvadze, 1978) - The Catalogue of 
       Trapezium Multiple Systems
    </title>
    <shortName> I/134/data </shortName>
    <identifier> ivo://CDS/VizieR/I/134/data </identifier>

    <curation>
      <publisher ivo-id="ivo://CDS/VizieR"> VizieR </publisher>
      <creator>
        <name>Salukvadze G.N.</name>
      </creator>
      <contributor>Francois Ochsenbein [CDS]</contributor>
      <date role="creation">1997-12-09</date>
      <version>11-Feb-1997</version>
      <contact>
        <name>CDS support team</name>
        <address>
          CDS, Observatoire de Strasbourg, 11 rue de l'Universite, 
          F-67000 Strasbourg, France
        </address>
        <email>question@simbad.u-strasbg.fr</email>
      </contact>
    </curation>

    <content>
      <subject>Multiple_Stars</subject>
      <description>
        The present catalogue of Trapezium-type Multiple Systems was
        compiled on the basis of the Index Catalogue of Visual Binary
        Stars (IDS, Jeffers et al., 1963). At the period of compilation
        of the Abastumani catalogue, IDS was the most complete catalogue
        concerning not only stars, but also the data on double
        stars. Besides giving relative positions, IDS presents the
        coordinates at 1900 and 2000 epochs, as well as in most cases
        magnitudes, spectral classes and proper motions. IDS contains
        all double and multiple stars from the North to the South poles
        with relative positions published up to the end of 1960, their
        total number being 64247. In order to select optimum value of K
        (ratio of the largest to the smallest distances among the
        components), which is the main criterion for relating a multiple
        star to the trapezium type, the dependence of the observed
        trapezia number on the K value has been analysed, and the value
        2.6 adopted for it. To exclude optical components, upper limits
        for the distances of faint components to the main star have been
        introduced, and the components fainter than 12.5mag were
        excluded altogether (Salukvadze, 1978). The catalogue of
        Trapezium-type Multiple Systems contains 412 trapezia, for
        which, after examining all main spectral catalogues (Jaschek et
        al., 1964; Kennedy et al., 1974; Houck et al., 1975;
        Cruz-Gonzales et al., 1974; Lindsey et al., 1968), spectral
        classes in the MK system have been specified. This was done for
        100 systems, including 65 stars of O and B spectral classes. The
        following data on trapezia are given in the catalogue:
        positional angles and distances, magnitudes and spectral classes
        according to HD as well as MK, the ADS and BD identification
        number of the main star. On the basis of the probability,
        deduced by Ambartsumian (1954), the number of pseudo-trapezia
        was estimated, that is, the number of multiple stars, which in
        fact have no trapezium-type configurations, but are observed as
        trapezia as a result of their projection on the celestial
        sphere. The number of estimated pseudo-trapezia is 167. It
        should be mentioned that among 59 trapezia, the main components
        of which are of the O-B2 spectral class, there are only 5
        pseudo-trapezia. This enables us to maintain that there is a
        considerable percent of real trapezia among the ones of
        mentioned spectral classes. Evaluation of the number of optical
        systems, formed as a result of the appearance of background
        stars in circles, which are determined by the upper limits of
        components' distances, led to their insignificant number 9. 
      </description>
      <source format="bibcode">1978AbaOB..49...39S</source>
      <referenceURL>
         http://vizier.u-strasbg.fr/cgi-bin/Cat?I/134/data
      </referenceURL>
      <type>Catalog</type>
      <contentLevel>Research</contentLevel>
    </content>

    <rights>public</rights>

    <format isMIMEType="true">text/xml+votable</format>
    <format isMIMEType="true">text/plain+csv</format>

    <coverage>
       <waveband>Optical</waveband>
    </coverage>

    <catalog>
      <table>
        <name>I/134/data</name>
        <description>The Catalogue of Trapezium Multiple Systems</description>

        <column>
          <name>recno</name>
          <description>
            Record number within the original table (starting from 1)
          </description>
          <unit/>
          <ucd>RECORD</ucd>
        </column>

        <column>
          <name>MainFlag</name>
          <description>
          [*] The asterisk indicates the main star of a trapezium system
          </description>
          <unit/>
          <ucd>REMARKS</ucd>
        </column>

        <column>
          <name>Seq</name>
          <description>Ordinal number</description>
          <unit/>
          <ucd>ID_MAIN</ucd>
        </column>

        <column>
          <name>IDS</name>
          <description>
            Designation in "Index Catalogue of Visual Double Stars"
            (based on B1900 position) 
          </description>
          <unit/>
          <ucd>ID_ALTERNATIVE</ucd>
        </column>

        <column>
          <name>Comp</name>
          <description>Designation of components</description>
          <unit/>
          <ucd>ID_ALTERNATIVE</ucd>
        </column>

        <column>
          <name>theta</name>
          <description>
            [0/360] Positional angle of a component relative to the main star
          </description>
          <unit>deg</unit>
          <ucd>POS_POS-ANG</ucd>
        </column>

        <column>
          <name>rho</name>
          <description>Distance of a component to the main star</description>
          <unit>arcsec</unit>
          <ucd>ORBIT_SEPARATION</ucd>
        </column>

        <column>
          <name>Vmag1</name>
          <description>? Magnitude of the main star (1)</description>
          <unit>mag</unit>
          <ucd>PHOT_MAG_UNDEF</ucd>
        </column>

        <column>
          <name>Vmag2</name>
          <description>? Magnitudes of trapezium component</description>
          <unit>mag</unit>
          <ucd>PHOT_JHN_V</ucd>
        </column>

        <column>
          <name>Sp1</name>
          <description>IDS Spectral class of the main star (1)</description>
          <unit/>
          <ucd>SPECT_TYPE_GENERAL</ucd>
        </column>

        <column>
          <name>SpType1</name>
          <description>
          Spectral class of the main star in the MK system (1)
          </description>
          <unit/>
          <ucd>SPECT_TYPE_GENERAL</ucd>
        </column>

        <column>
          <name>ADS</name>
          <description>? ADS number (1)</description>
          <unit/>
          <ucd>ID_ALTERNATIVE</ucd>
        </column>

        <column>
          <name>DM</name>
          <description>Durchmusterung number (1)</description>
          <unit/>
          <ucd>ID_ALTERNATIVE</ucd>
        </column>
      </table>
    </catalog>

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