Catalog of Components of Double and Multiple Stars
Encyclopedia
The Catalog of Components of Double and Multiple Stars, or CCDM, is an astrometric
star catalogue
of double
and multiple
star
s. It was made by Jean Dommanget and Omer Nys at the Royal Observatory of Belgium
in order to provide an input catalogue of stars for the Hipparcos
mission. The published first edition of the catalog, released in 1994, has entries for 74,861 components of 34,031 double and multiple stars; the second edition, in 2002, has been expanded to provide entries for 105,838 components of 49,325 double and multiple stars. The catalog lists positions, magnitude
s, spectral types, and proper motion
s for each component.
Astrometry
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
star catalogue
Star catalogue
A star catalogue, or star catalog, is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some...
of double
Double star
In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because the pair forms a binary star, i.e...
and multiple
Multiple star
A multiple star consists of three or more stars which appear from the Earth to be close to one another in the sky. This may result from the stars being physically close and gravitationally bound to each other, in which case it is physical, or this closeness may be merely apparent, in which case...
star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s. It was made by Jean Dommanget and Omer Nys at the Royal Observatory of Belgium
Observatoire Royal de Belgique
The Royal Observatory of Belgium, officially known in French as the Observatoire Royal de Belgique, and in Dutch as the Koninklijke Sterrenwacht van België, is situated at Uccle since 1890, although it was originally founded in 1834...
in order to provide an input catalogue of stars for the Hipparcos
Hipparcos
Hipparcos was a scientific mission of the European Space Agency , launched in 1989 and operated between 1989 and 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky...
mission. The published first edition of the catalog, released in 1994, has entries for 74,861 components of 34,031 double and multiple stars; the second edition, in 2002, has been expanded to provide entries for 105,838 components of 49,325 double and multiple stars. The catalog lists positions, magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
s, spectral types, and proper motion
Proper motion
The proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...
s for each component.