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Multicolour CCD measurements of visual double and multiple stars. III
Context: Recent CCD observations were performed in the period 1998-2004for a large sample of visual double and multiple stars selected from theHipparcos Catalogue and/or from the Gliese Catalogue of Nearby Stars. Aims: Accurate astrometric and photometric data allowing us tocharacterise the individual components are provided. These data arecompared to Hipparcos data or to data from an older epoch to assess thenature of the observed systems. Methods: We simultaneously apply aMoffat-Lorentz profile with a similar shape to all detected componentsand adjust the profile parameters from which we obtain the relativeastrometric position (epoch, position angle, angular separation) as wellas differential multi-colour photometry (filters (B)VRI). Results: Wethus acquired recent data for 71 visual systems of which 6 are orbitalbinaries, 27 are nearby, and 30 are multiple systems. In three of thesecases, the systems remained unresolved. 23 new components were detectedand measured. Two new visual double stars of intermediate separationwere also found. The estimated accuracies in relative position are0.04° and 0.01 arcsec respectively, while those in differentialphotometry are of the order of 0.01-0.02 mag in general. Conclusions:.The nature of the association of 55 systems is evaluated. New basicbinary properties are derived for 20 bound systems. Component coloursand masses are provided for two orbital binaries.Based on observations collected at the National AstronomicalObservatory, Rozhen, and the Astronomical Observatory, Belogradchik,both operated by the Institute of Astronomy, Bulgarian Academy ofSciences. Also based on data obtained by the Hipparcos astrometrysatellite. Appendix A is only available in electronic form athttp://www.aanda.org Tables 4-6 are only available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/464/641
| CCD Measurements of Double and Multiple Stars at NAO Rozhen. II
Using the 2-m telescope of the Bulgarian National AstronomicalObservatory at Rozhen observations of twenty multiple stars were carriedout during one whole night - October 30/31, and, also, during the firsthalf of the next one - October 31, 2005. This is the second series ofCCD measurements of double and multiple stars done at Rozhen. In thepaper we present the results for the position angle and separation foreleven multiple stars (35 pairs) which could have been measured.
| CCD Measurements of Double and Multiple Stars at NAO Rozhen
With the 2-m telescope of the Bulgarian National AstronomicalObservatory at Rozhen observations of fifteen multiple stars werecarried out during one night - October 17/18, 2004. In the paper wepresent the results for the position angle and separation for tenmultiple stars (27 pairs) which could be measured.
| Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution
The kinematics of 237 chromospherically active binaries (CABs) werestudied. The sample is heterogeneous with different orbits andphysically different components from F to M spectral-type main-sequencestars to G and K giants and supergiants. The computed U, V, W spacevelocities indicate that the sample is also heterogeneous in velocityspace. That is, both kinematically younger and older systems exist amongthe non-evolved main sequence and the evolved binaries containing giantsand subgiants. The kinematically young (0.95 Gyr) subsample (N= 95),which is formed according to the kinematical criteria of moving groups,was compared with the rest (N= 142) of the sample (3.86 Gyr) toinvestigate any observational clues of binary evolution. Comparing theorbital period histograms between the younger and older subsamples,evidence was found supporting the finding of Demircan that the CABs losemass (and angular momentum) and evolve towards shorter orbital periods.The evidence of mass loss is noticeable on the histograms of the totalmass (Mh+Mc), which is compared between theyounger (only N= 53 systems available) and older subsamples (only N= 66systems available). The orbital period decrease during binary evolutionis found to be clearly indicated by the kinematical ages of 6.69, 5.19and 3.02 Gyr which were found in the subsamples according to the periodranges of logP<= 0.8, 0.8 < logP<= 1.7 and 1.7 < logP<=3, respectively, among the binaries in the older subsample.
| Determining the Minimum Sum of the Component Masses for a Binary with a Known Parallax from Observations of a Short Arc of Its Apparent Motion
An inequality that allows the minimum sum of the component masses for abinary, M_0, to be determined was derived from simple geometricconsiderations. This quantity satisfies the observed orbital motionaccording to Newton's law with a known parallax. The M_0 value can becalculated if the apparent-motion parameters for the components,including the curvature of the observed short orbital arc, weredetermined from observations. We estimated M_0 for 14 Pulkovo programstars for which the apparent orbital arc covered with observations wasno less than 10 deg. We compare M_0 with the masses estimated from themass-luminosity relation. A significant mass excess was found for thestar ADS 10329.
| Statistics of spectroscopic sub-systems in visual multiple stars
A large sample of visual multiples of spectral types F5-M has beensurveyed for the presence of spectroscopic sub-systems. Some 4200 radialvelocities of 574 components were measured in 1994-2000 with thecorrelation radial velocity meter. A total of 46 new spectroscopicorbits were computed for this sample. Physical relations are establishedfor most of the visual systems and several optical components areidentified as well. The period distribution of sub-systems has a maximumat periods from 2 to 7 days, likely explained by a combination of tidaldissipation with triple-star dynamics. The fraction of spectroscopicsub-systems among the dwarf components of close visual binaries withknown orbits is similar to that of field dwarfs, from 11% to 18% percomponent. Sub-systems are more frequent among the components of widevisual binaries and among wide tertiary components to the known visualor spectroscopic binaries - 20% and 30%, respectively. In triple systemswith both outer (visual) and inner (spectroscopic) orbits known, we findan anti-correlation between the periods of inner sub-systems and theeccentricities of outer orbits which must be related to dynamicalstability constraints. Tables 1, 2, and 6 are only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/382/118
| Kinematics of Hipparcos Visual Binaries. II. Stars with Ground-Based Orbital Solutions
This paper continues kinematical investigations of the Hipparcos visualbinaries with known orbits. A sample, consisting of 804 binary systemswith orbital elements determined from ground-based observations, isselected. The mean relative error of their parallaxes is about 12% andthe mean relative error of proper motions is about 4%. However, even 41%of the sample stars lack radial velocity measurements. The computedGalactic velocity components and other kinematical parameters are usedto divide the stars with known radial velocities into kinematical agegroups. The majority (92%) of binaries from the sample are thin diskstars, 7.6% have thick disk kinematics and only two binaries have halokinematics. Among them, the long-period variable Mira Ceti has a verydiscordant {Hipparcos} and ground-based parallax values. From the wholesample, 60 stars are ascribed to the thick disk and halo population.There is an urgent need to increase the number of the identified halobinaries with known orbits and substantially improve the situation withradial velocity data for stars with known orbits.
| An Astrometric Study of the Triple Star ADS 48
We analyze the series of relative positions of the hierarchical triplesystem ADS 48 ABF (AB = 6 arcsec, AF = 327 arcsec) obtained with the26-inch Pulkovo refractor during 1961-1995 and measured with theFantazia automated measuring system. A new relative orbit of pair AB isdetermined by the method of apparent-motion parameters using newobservations and all the available astrometric and astrophysical data onthis star, including its Hipparcos parallax. The new orbit for pair ABis reliably reconciled with all the new and previous observations ofthis star for the sum of the components' masses equal to 1.4 M_solar.The Pulkovo observations (1961-1995) revealed a perturbation with aperiod of 15 years and an amplitude rho ~ 0.01 arcsec, suggesting thepresence of an unseen companion with a mass as large as 0.05 M_solar.Since the oscillation amplitude is at a noise level, the orbit of thesuspected companion cannot be determined. Assuming that stars A and Bhave the same mass, which corresponds to astrophysical data, we computedthe parameters of apparent motion of component F relative to the centerof mass of system AB and determined the family of orbits that satisfiedthe Pulkovo observations. All the computed orbits are steeply (more than55 deg) inclined to the orbital plane of AB. The orbital motion of starF has been investigated for the first time.
| Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
| CCD measurements of visual double stars from the German-Spanish Astronomical Center at Calar Alto
342 CCD measurements of relative positions and magnitude differences for145 visual double stars are presented. Observations were carried out atthe 1.23m telescope of the German-Spanish Astronomical Center at CalarAlto (Spain), all of them in V and R photometric bands.
| Photometric Measurements of the Fields of More than 700 Nearby Stars
In preparation for optical/IR interferometric searches for substellarcompanions of nearby stars, we undertook to characterize the fields ofall nearby stars visible from the Northern Hemisphere to determinesuitable companions for interferometric phase referencing. Because theKeck Interferometer in particular will be able to phase-reference oncompanions within the isoplanatic patch (30") to about 17th magnitude atK, we took images at V, r, and i that were deep enough to determine iffield stars were present to this magnitude around nearby stars using aspot-coated CCD. We report on 733 fields containing 10,629 measurementsin up to three filters (Gunn i, r and Johnson V) of nearby stars down toabout 13th magnitude at V.
| CCD Observations of Visual Double and Multiple Stars at the Belgrade Observatory
The author presents her CCD measurements of 105 double and multiplestars performed with a ST-6 camera on the Belgrade Large Refractor(Zeiss 65/1055 cm).
| The Age Range of Hyades Stars
On the basis of canonical models, the age of Hyades supercluster stars,whether in the Hyades and Praesepe clusters or the noncluster field,ranges from (5-6) x 10^8 to 10^9 yr. The difference between the parallaxderived from the supercluster motion and that obtained from Hipparcosobservations has a dispersion only twice that of the mean dispersion ofthe individual Hipparcos values. The supercluster appears not to containred giants on the first ascent of the red giant branch, but onlyasymptotic giant branch (``clump'') stars. The masses obtained forindividual components of binary stars in the supercluster show adispersion of less than 10% when compared with model predictions.
| New orbits.
Not Available
| MSC - a catalogue of physical multiple stars
The MSC catalogue contains data on 612 physical multiple stars ofmultiplicity 3 to 7 which are hierarchical with few exceptions. Orbitalperiods, angular separations and mass ratios are estimated for eachsub-system. Orbital elements are given when available. The catalogue canbe accessed through CDS (Strasbourg). Half of the systems are within 100pc from the Sun. The comparison of the periods of close and widesub-systems reveals that there is no preferred period ratio and allpossible combinations of periods are found. The distribution of thelogarithms of short periods is bimodal, probably due to observationalselection. In 82\% of triple stars the close sub-system is related tothe primary of a wide pair. However, the analysis of mass ratiodistribution gives some support to the idea that component masses areindependently selected from the Salpeter mass function. Orbits of wideand close sub-systems are not always coplanar, although thecorresponding orbital angular momentum vectors do show a weak tendencyof alignment. Some observational programs based on the MSC aresuggested. Tables 2 and 3 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| CCD measurements of double and multiple stars in Belgrade
The CCD measurements for 123 double stars with ST-6 camera attached tothe Zeiss 65/1055 cm Refractor of the Belgrade Observatory arecommunicated. Table 1 only available in electronic form, Table 2 also inelectronic form at CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html}}
| The ROSAT All-Sky Survey of Active Binary Coronae. III. Quiescent Coronal Properties for the BY Draconis--Type Binaries
We present X-ray observations of 35 active late-type BY Draconis dwarfbinary systems and 28 evolved binary systems, similar in nature to theRS Canum Venaticorum systems, obtained with the Position SensitiveProportional Counter (PSPC) during the ROSAT All-Sky Survey phase of themission. Of this sample, 52 targets were detected in exposures ofroughly 600 s or less. When these new data are combined with the earlierresults from Dempsey et al. (1993b), this survey represents the largestsample of active binary systems observed to date at any wavelength,including X-rays. We expand our investigation of how coronal properties(e.g., surface flux, luminosity, etc.) correlate with stellar parameters(e.g., rotation period, color, etc.) and confirm the conclusions ofDempsey et al. (1993b). Rotation period provides the best correlationwith X-ray surface flux with F_{{X}}~P^{-0.59+/-0.10}_{{rot}} for theentire sample. We find no evidence for a "basal" or nonmagnetic X-rayflux component. We model the low-resolution pulse-height spectra for 12systems with two-temperature thermal plasmas. The derived temperaturesfor the BY Dra systems are identical to those previously derived foractive evolved giants and subgiants in close binaries (Dempsey et al.1993c). We also show that the dependence of temperature and emissionmeasures on rotation period is the same for the dwarf, subgiant, andgiant binaries.
| New orbits.
Not Available
| Not Available
Not Available
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| Dynamics of nearby multiple stars. The alpha Centauri system
The triple star system alpha Cen AB and Proxima Cen - the component C -is the nearest to the Sun. The study of its dynamics has shown that thissystem is probably not a chance one. The motion of the component C(Proxima) with respect to the center of mass of the pair AB ishyperbolic with the probability P = 1.0. We observe, therefore, a slowpassage of C close to the pair AB. We propose the hypothesis that thissystem is a part of a stellar moving group. We list the probable membersof this group amongst the nearby stars. Amongst them we have thebinaries Gliese 140.1 and 676, the triple system ADS 10288 (Gliese649.1), and six single stars. The probability to find these stars bychance inside the velocity space cube with a side of 20 km/s aroundalpha Cen is equal to about 2%.
| Radial velocities of the components of wide visual double stars.
Not Available
| Micrometer measurements of visual double stars made at the Spanish observatories at Calar Alto and Fabra
The study presents 184-micrometer measurements of 100 double starsobserved with the 152-cm telescope at Calar Alto (Almeria, Spain) andthe 38-cm refractor at Fabra Observatory (Barcelona, Spain). The epoch,observed position angle, angular distance between components, number ofnights on which the star was observed, and an indication of the observerare given. Orbits were calculated for almost all the observed stars.
| A catalog of chromospherically active binary stars (second edition)
The catalog contains 206 spectroscopic binary systems with at least onelate-type component that shows Ca II H and K emission in its spectrum.These systems include the classical RS CVn binaries and BY Dra binaries.The catalog summarizes information on the photometric, spectroscopic,orbital, and physical properties of the systems as well as space motionsand positions. Up to 42 'parameters' for each stellar system are listedfollowed by the appropriate reference to direct interested colleagues tothe original papers. A comprehensive selection of further informationfor each star is given in the individual notes. In addition, the catalogcontains a candidate list of 138 stars that have similar characteristicsbut are not definitely known binaries or have not had Ca II H and Kemission observed.
| Photometry of dwarf K and M stars
An observational program using UBVRI photometry is presented for 688stars from among the dwarf K and M stars already found spectroscopicallyby Vyssotsky (1958). Of these, 211 have not been observedphotometrically. These observations were obtained over a period ofseveral years at the Kitt Peak National Observatory using a GaAsphotomultiplier with an 0.9 m reflector. Based on night-to-nightvariations in the measures of individual stars, the internal errors maybe estimated to be roughly 0.01 mag for the colors and 0.015 for the Vmagnitudes. The photometric parallaxes reported for each star werecomputed in the manner discussed by Weis (1986).
| Orbits of visual binaries
The paper presents orbit computations of 20 pairs of visual binarieswith recent reobservations in 1991.0-1992.5. Fourteen of the pairs wereobserved at Cerro Tololo; the other six were studied in connection withastrometric plate series.
| Photographic astrometry of binary and proper-motion stars. VII
Parallax data and mass ratios are presented for astrometric binaries andproper-motion stars. Three new unresolved red dwarf binaries are listedand annotated.
| Observations of double stars and new pairs. XV
The study reports visual and photographic measures listed for 1150 pairsobtained in the time frame 1989.91-1992.15, including 221 new doublestars. Magnitudes were estimated for a part of the objects, especiallythe fainter ones. Plate orientations were calculated from field stars ofknown positions and were precessed to the epoch; numbers of nights andof measured exposures are given. Reobservation of faint, neglected pairsreveal many corrections to the data from the old discovery lists.
| Kinematics and age of RS Canum Venaticorum and by Draconis stars
Space velocities of 146 chromospherically active binary stars have beencalculated. Containing F-M spectral types on the main sequence togetherwith G and K giants and subgiants, this very heterogeneous sample hasbeen divided into groups in order to segregate stars which have similarkinematics and ages. After many trials for different criteria, thesample was divided into five groups - two groups for giants, two groupsfor main-sequence systems, and one group for main-sequence systems.Kinematics of subgiants implies a stellar age of about 2-3 Gyr. Youngand old groups of giants and main-sequence systems could becharacterized by a kinematical age of about 1 Gyr and more than 5 Gyr,respectively. These ages are estimated approximately according to spacevelocity distributions and dispersions in velocity space in each group.Inferred ages for the groups above agrees with circulation, rotationactivity relation, and stellar evolution theories.
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