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

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.

1995 ◽  
Vol 166 ◽  
pp. 395-395 ◽  
Author(s):  
J. Dommanget ◽  
O. Nys

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.


1992 ◽  
Vol 135 ◽  
pp. 403-411
Author(s):  
F. Mignard ◽  
M. Badiali ◽  
P.L. Bernacca ◽  
H. Bernstein ◽  
D. Cardini ◽  
...  

AbstractAfter the processing of one year of observations carried out by HIPPARCOS it is possible to provide quantitative results as to the number of new double and multiple stars to be detected and the real capacity of this mission to perform relative astrometry on double stars. We present and discuss the methods developed to this end and include the first results concerning the detection statistics and the determination of separation and position angle for double stars. About 16,000 stars have been recognized as non-single, including 9,000 already known as double and mutliple before the mission. Also, a subset of 10,500 stars have been successfully solved for their relative coordinates with an accuracy in the range of 3 to 10 mas.


1992 ◽  
Vol 135 ◽  
pp. 339-342
Author(s):  
E. Oblak ◽  
P. Lampens

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.


1992 ◽  
Vol 9 ◽  
pp. 421-421
Author(s):  
S. Söderhjelm ◽  
D.W. Evans ◽  
F. van Leeuwen ◽  
L. Lindegren

AbstractThe Hipparcos satellite has a predefined observing program given by an Input Catalogue with 118 000 entries. This includes some 10 000 members of known double or multiple systems (with separations above 0.1 arcsec and magnitude-differences below 4-5), which are observably non-single and thus need a more complex reduction procedure. Also, a similar number of hitherto unknown doubles showing deviations from a single-star observation model will be included in the double-star reductions. A key feature in the NDAC reductions is the use of the main reduction results to calibrate and collect the data for individual doubles in ‘Case History Files’. This enables a global solution of both absolute and relative parameters for a double to be carried out later in a single solution. Using provisional data tapes covering small parts of a 14-month interval, tests have been made of major parts of the double star reductions. Comparisons with the main reduction results for single stars indicate that remaining calibration errors are below the 10 milliarcsec level. For known doubles, the solutions are good relative to the Input Catalogue at the expected 0.3 arcsec level, and for a few tens of systems observed with the star-mapper, the agreement is at the 0.05 arcsec level. A few hundred doubles not flagged in the Input Catalogue have also been detected and had their parameters provisionally determined. A detailed paper describing these methods and results has been accepted by Astronomy & Astrophysics.


1992 ◽  
Vol 135 ◽  
pp. 435-438
Author(s):  
J. Dommanget ◽  
P. Lampens

AbstractNow that the HIPPARCOS satellite safely revolves on its “degraded” orbit — after the exploit of the ESA technicians to rescue it from the faulty ignition of its apogeum boost motor — and regularly provides the information expected for reaching the initial aim of the project, one may turn to examine the possible exploitation of the final HIPPARCOS Catalogue.In the present paper, we describe how double and multiple stars have been introduced in the Input Catalogue and what may be expected from their observation. We also try to evaluate how much the final HIPPARCOS data may influence future researches on these celestial bodies and what kind of ground–based observation programmes should be conducted in order to support the space results.


1988 ◽  
Vol 98 ◽  
pp. 93-94
Author(s):  
P. Durand

The Double Star Section of the Société Astronomique de France has been in existence since 1980. It has set up observing groups covering various areas: close binaries, photographic measurements, re-observation of neglected pairs, and astrolabe measurements. All this has been thanks to our sceintific advisors, professionals specializing in double stars: Muller, Couteau, Soulié, Bacchus, and Dommanget. The Section meets twice a year, and it was at Lille in 1984 that J. Dommanget suggested that we should collaborate in the programme of identifying doubtful doubles for the input catalogue for the future satellite Hipparcos.The first observations were made after the meeting in November 1984, from Paris and with amateur equipment, thanks to an initial list prepared by Prof. Bacchus. After several months we could tell that our equipment was insufficient, and that photocopies of the Palomar Sky Survey were not accurate enough. We needed more powerful instruments and a different organisation to resolve the ambiguity in identification that can arise by two close stars being confused and given the same coordinates, by the presence of a cluster, or by the existence of a faint star that is not given in the catalogues. In all these cases, identifying the star means being able to give it a designation, allowing it to be found on an atlas, and obtaining better coordinates so that the ambiguity is removed. It is a question of astrometry.


1992 ◽  
Vol 9 ◽  
pp. 423-423
Author(s):  
M. Frœschle ◽  
F. Mignard ◽  
J.L. Falin

AbstractHipparcos observations provide a wealthy source of discovery of new double and multiple stars. We have developed adequate procedures to recognize in the signal parameters the multiplicity of the stellar source passing through the Hipparcos field of view. These procedures are outlined together with the design of the statistical tests employed. Sampling on real data indicates that about 6000 new double stars will be detected at the mission completion.


1988 ◽  
Vol 98 ◽  
pp. 122-127
Author(s):  
D. Rodriguez ◽  
J.A. Bernedo ◽  
D. Valls-Gabaud

We present a new technique in double star photography leading to high accuracy measurements in amateur-size instruments. The trailing method has been improved by the use of a chopper that cuts the trail into a number of segments. The chopper period is accurately known, so it is the length of each segment on the plate. In this way the scale factor is measured in each exposure. Fine-grain films, such as hyper-sensitized Kodak 2415, are used and all measurements are performed at the microscope. The same technique may also be applied to CCD cameras. A statistical analysis of errors shows that Δθ ≤ 30′ and Δρ/ρ ≈ 0.01 for most binaries with ρ ≥ 3″. This method has been applied to professional-amateur joint programs dealing with multiple systems with variable components and a survey of poorly-observed wide binaries.


1995 ◽  
Vol 166 ◽  
pp. 69-76
Author(s):  
F. Mignard

As we approach the final processing of the observations carried out by HIPPARCOS, in particular for the double and multiple stars, it is possible to provide reliable statistics on the number of such objects detected and on the quality of the relative and absolute astrometry and photometry. About 24 000 stars have been recognized as non-single, including 11 000 already known as double and multiple before the mission and 13000 discovered by Hipparcos. Also, a subset of 16 000 stars among the 24 000 have been successfully solved for their relative coordinates (position angle and separation) with an accuracy in the range of 3 to 30 mas, including 7000 new double stars. I outline in this paper the principle of the internal recognition procedure and present some statistics on the solution.


2000 ◽  
pp. 101-103
Author(s):  
D. Olevic ◽  
Z. Cvetkovic ◽  
M. Dacic

The Hipparcos-Input Catalogue also contains about 8000 already known visual double stars. In the framework of this-project campaign, in addition to other parameters, were also determined the parallaxes ?, as well as the polar coordinates ? and ? for double stars. On the basis of a comparison of these data to those obtained earlier from the ground based measurements (WDS Catalogue) statistical examinations of a double-star sample (1' ? ? ? 14') are performed. It is shown that an exceptionally good agreement exists of the statistical distribution ??/?t of the sample as function of ?(AU) and the curve ? = C(?)/?2 representing the II Kepler law.


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