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 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 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 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.

Spectroscopic Observations of Visual Double Stars

1965 ◽  
Vol 5 ◽  
pp. 109-111
Author(s):  
Frederick R. West
Keyword(s):  
Radial Velocity ◽  
High Dispersion ◽  
Velocity Difference ◽  
Spectrograph Slit ◽  
Spectroscopic Observations ◽  
Double Stars ◽  
Visual Double Stars ◽  
Relative Orbit ◽  
Two Component ◽  
Star Images

There are certain visual double stars which, when close to a node of their relative orbit, should have enough radial velocity difference (10-20 km/s) that the spectra of the two component stars will appear resolved on high-dispersion spectrograms (5 Å/mm or less) obtainable by use of modern coudé and solar spectrographs on bright stars. Both star images are then recorded simultaneously on the spectrograph slit, so that two stellar components will appear on each spectrogram.

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