scholarly journals Observational Programme for Classical and CCD Photometry of Visual Double and Multiple Systems

1992 ◽  
Vol 135 ◽  
pp. 339-342
Author(s):  
E. Oblak ◽  
P. Lampens
Keyword(s):  
Photometric Data ◽  
European Network ◽  
Ccd Photometry ◽  
Multiple Systems ◽  
Double Stars ◽  
Visual Double Stars ◽  
Astrometric Data ◽  
Input Catalogue ◽  
Colour Indices

Complementary accurate photometric data with astrophysical content are needed for a well-chosen sample of binaries and multiple systems for which good-quality astrometric data already exist or will soon be available. The observational programme, started in the context of the European Network of Laboratories “Visual Double Stars” (Oblak et al. 1992), is therefore based on samples extracted from the “Catalogue des Composantes d’Etoiles Doubles et Multiples” (CCDM, Dommanget, 1989) and reported in Annex 1 (Double and Multiple Systems) of the HIPPARCOS Input Catalogue (C. Turon et al. 1992).Systems with components in the HIPPARCOS Input Catalogue are selected for which the present photometric information is poor, i.e. not all components have been observed or they have colour indices and/or magnitudes of insufficient quality for extraction of astrophysical quantities (Figure 1).Observations, performed in various observatories located in both hemispheres, must yield both classical and CCD photometric campaigns.

scholarly journals The European Network of Laboratories: Visual Double Stars

1992 ◽  
Vol 135 ◽  
pp. 454-456 ◽  
Author(s):  
E. Oblak ◽  
A.N. Argue ◽  
P. Brosche ◽  
J. Cuypers ◽  
J. Dommanget ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Photometric Data ◽  
Selection Effects ◽  
Spectral Classification ◽  
European Network ◽  
Double Stars ◽  
Visual Double Stars ◽  
Ccd Detectors ◽  
Colour Indices ◽  
Space Observations

The study of double stars has since long been recognized as a basic key to the understanding of star formation and stellar evolution. Moreover, close visual double stars have always been systematically neglected in photometric observational programmes although they contain an important part of physically associated systems. It is then timely to organize major observational programmes of these objects for a number of good reasons:1.The frequency of double stars is continuously reviewed and the rate of their detection is steadily increasing — both from ground–based and space observations — in such a way that they no longer can be discarded in any models of galactic structure;2.Space observations (HIPPARCOS, HST) significantly improve the quality and the importance of stellar samples and permit to better take into account some of the selection effects;3.The high–quality astrometric (and also photometric) data that will be provided for such systems by the space observations should be matched with accurate and homogeneous complementary astrophysical information such as colour indices and spectral classification. Such information for close visual double stars is unfortunately almost non-existent but are now being more easily accessible with the use of CCD detectors.

scholarly journals Astrometric Standard Fields for CCD Observations of Double Stars

1994 ◽  
Vol 161 ◽  
pp. 291-293
Author(s):  
D. Sinachopoulos ◽  
E. Oblak ◽  
M. Geffert ◽  
J. Colin ◽  
J.-F. LeCampion ◽  
...  
Keyword(s):  
Scientific Community ◽  
Photometric Data ◽  
Stellar Systems ◽  
European Network ◽  
Multiple Star ◽  
Double Stars ◽  
Visual Double Stars ◽  
Ccd Observations ◽  
Formation And Evolution ◽  
Selection Of

The number of known double stars is steadily increasing, thanks to ground-based and space observations. Therefore the ratio of known double to single stars has to be revised upwards continuously. With the Hipparcos parallaxes it will be possible to get stellar statistics for precisely defined volumes of space. This will lead to strong constraints on all astrophysical calibrations of masses, spectral types and luminosities in the solar neighbourhood. A European network of laboratories was created in August 1990 in order to remedy the lack of photometric data for close visual double stars. This network intends to study all aspects of formation and evolution of double and multiple star systems. The immediate goal of the group is to provide the scientific community with a compilation of known photometric data on a large selection of close visual double stars and to significantly enlarge this information by new observations with modern devices. A photometric database of stellar systems is being compiled from most widely used photometric systems in collaboration with the ‘Centre de Données Stellaires’ of Strasbourg.

scholarly journals CCD Photometry of Hipparcos Stellar Systems

1995 ◽  
Vol 166 ◽  
pp. 390-390
Author(s):  
E. Oblak ◽  
M. Chareton
Keyword(s):  
Photometric Data ◽  
Stellar Systems ◽  
Ccd Photometry ◽  
Double Stars ◽  
Visual Double Stars ◽  
Ccd Detectors

With the introduction of CCD detectors, it now appears feasible to obtain accurate photometric data for each of the components of close visual double stars with an angular separations between 1 and 12″.

scholarly journals UBV CCD Photometry of “Close” Visual Double Stars

1992 ◽  
Vol 135 ◽  
pp. 362-364
Author(s):  
E. Van Dessel ◽  
D. Sinachopoulos ◽  
P. Prado
Keyword(s):  
Ccd Cameras ◽  
Ccd Photometry ◽  
Astrophysical Interest ◽  
Double Stars ◽  
Visual Double Stars ◽  
Ubv Photometry ◽  
Visual Binaries

AbstractWe use the CCD cameras of the 61-cm UTSO and the 90-cm Dutch telescopes of the Las Campanas and European Southern Observatories respectively in order to perform UBV photometry of visual double stars.Our sample contains southern visual binaries with A–type (470 pairs) and G–type primaries (170 pairs), which have angular separations mainly between 1″.5 and 5″. The double stars of our sample have been selected from the WDS according to their astrophysical interest and the technological limits of contemporary CCDs.

scholarly journals The Catalogue of the Components of Double and Multiple Stars (CCDM) - First Edition

1995 ◽  
Vol 166 ◽  
pp. 395-395 ◽  
Author(s):  
J. Dommanget ◽  
O. Nys
Keyword(s):  
Data Base ◽  
Multiple Star ◽  
Multiple Systems ◽  
Double Stars ◽  
Multiple Stars ◽  
Double And Multiple Stars ◽  
General Data ◽  
Input Catalogue ◽  
Better Than

The Hipparcos mission required the realisation of an Input Catalogue giving the positions of 100.000 stars (single or components of double and multiple systems) to an accuracy better than 1″5. At the start of this work (1981) no specific catalogue of double and multiple stars provided these data. The only general data base on double stars available to us, giving positions to ±1′, was the Index (1961,0) updated at the USNO by C. E. Worley till 1976,5 and of which a copy was communicated by P. Muller of the Observatoire de Meudon. It has then been decided to reformat this Catalogue in such a way as to allow the introduction of all necessary information for the mission. This permitted a correct cross-identification with the Hipparcos Input Catalogue (of finally 118.000 stars). It was later called: the Catalogue of the Components of Double and Multiple stars (CCDM). Since then, it has been developed and its aim remains to furnish the best accurate locations and descriptions of the double and multiple systems on the sky for all double and multiple star research.

scholarly journals Archives of Photometric Data

1992 ◽  
Vol 9 ◽  
pp. 725-726 ◽  
Author(s):  
J.-C. Mermilliod
Keyword(s):  
Data Retrieval ◽  
Photometric Data ◽  
Multiple Systems ◽  
Double Stars ◽  
Definition Of

The process of archiving photometric data and compiling catalogues is in principle easy to solve, but, in practice, does not appear so simple. Data retrieval may become difficult and inefficient if sufficient care is not taken to solve the general problems which are encoutered: (i) the lack of definition of fundamental identificators; (ii) the lack of coordinates for thousands of faint stars; (iii) the innacuracy of the identification and description of the components observed in double stars or multiple systems: A, B, C, AB, or BC; (iv) the fact that the number of observations is often not published.

scholarly journals HIPPARCOS First Results in the Double Star Photometry

1992 ◽  
Vol 135 ◽  
pp. 421-428
Author(s):  
F. Mignard ◽  
J.L. Falin ◽  
M. Froeschlé
Keyword(s):  
Double Star ◽  
Multiple Systems ◽  
Double Stars ◽  
Multiple Stars ◽  
Accuracy And Precision ◽  
First Results ◽  
Main Detector ◽  
Input Catalogue ◽  
Magnitude Difference ◽  
Better Than

AbstractIn addition to its astrometric capabilities the HIPPARCOS main detector proves to be a good phototometer. The main features of the photometric reduction applied to double stars are outlined. We show how it is possible to discriminate single stars from multiple stars from the photometric signal. Results presented are based on about 16000 stars recognized as non-single, of which 8000 were not known to be double in the HIPPARCOS Input Catalogue. Magnitudes for multiple systems as a whole are derived with a precision usually better than 0.005 mag while the magnitude of each component is recovered up to magnitude difference of 3 mag, but with less accuracy and precision.

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