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New GCVS Versions for Three Southern Constellations
We are currently working on a version of the General Catalogue ofVariable Stars (GCVS) revised taking into account the new dataaccumulated since the 4th GCVS edition. A draft new version will bereleased for each constellation as soon as the work for theconstellation is finished. It will contain all stars of the 4th GCVSedition plus a complete catalogue of the stars added to the GCVS in theName Lists of Variable Stars Nos. 67 - 78. Now we are ready for thefirst release, containing more than 1300 variable stars in theconstellations of Antlia, Ara, and Telescopium. When preparing therelease, we actively used modern data-mining possibilities to improvevariability types and light elements. This paper introduces the firstrelease of the new GCVS version and presents new results (types, lightelements), based mainly on data mining, for 213 stars.
| Contact Binaries with Additional Components. I. The Extant Data
We have attempted to establish observational evidence for the presenceof distant companions that may have acquired and/or absorbed angularmomentum during the evolution of multiple systems, thus facilitating orenabling the formation of contact binaries. In this preliminaryinvestigation we use several techniques (some of themdistance-independent) and mostly disregard the detection biases ofindividual techniques in an attempt to establish a lower limit to thefrequency of triple systems. While the whole sample of 151 contactbinary stars brighter than Vmax=10 mag gives a firm lowerlimit of 42%+/-5%, the corresponding number for the much better observednorthern-sky subsample is 59%+/-8%. These estimates indicate that mostcontact binary stars exist in multiple systems.
| A catalogue of eclipsing variables
A new catalogue of 6330 eclipsing variable stars is presented. Thecatalogue was developed from the General Catalogue of Variable Stars(GCVS) and its textual remarks by including recently publishedinformation about classification of 843 systems and making correspondingcorrections of GCVS data. The catalogue1 represents thelargest list of eclipsing binaries classified from observations.
| Searching for unknown open clusters in the Tycho-2 catalog
We present 11 new open cluster candidates found in a systematic searchfor unknown star clusters using the astrometric and photometric dataincluded in the Tycho 2 catalog. The possible existence of these stellaraggregates is supported by the analysis of proper motions,color-magnitude diagrams, stellar density distributions, and by thevisual inspection of the Digitized Sky Survey (DSS) plates. With thesetools we were able to determine mean absolute proper motions as well aspreliminary reddenings, distances and ages for the majority of thecandidates. We found that most of them are possibly nearby (closer than~ 600 pc) open clusters never studied before.Based on observations of the ESA Hipparcos satellite.Figures 1 and 2 are only available in electronic form athttp://www.edpsciences.org
| The 7.5 Magnitude Limit Sample of Bright Short-Period Binary Stars. I. How Many Contact Binaries Are There?
A sample of bright contact binary stars (W UMa type or EW, and related:with β Lyr light curves, EB, and ellipsoidal, ELL-in effect, allbut the detached, EA) to the limit of Vmax=7.5 mag is deemedto include all discoverable short-period (P<1 day) binaries withphotometric variation larger than about 0.05 mag. Of the 32 systems inthe final sample, 11 systems have been discovered by the Hipparcossatellite. The combined spatial density is evaluated at(1.02+/-0.24)×10-5 pc-3. The relativefrequency of occurrence (RFO), defined in relation to the main-sequencestars, depends on the luminosity. An assumption of RFO~=1/500 forMV>+1.5 is consistent with the data, although the numberstatistics is poor with the resulting uncertainty in the spatial densityand the RFO by a factor of about 2. The RFO rapidly decreases forbrighter binaries to a level of 1/5000 for MV<+1.5 and to1/30,000 for MV<+0.5. The high RFO of 1/130, previouslydetermined from the deep OGLE-I sample of disk population W UMa typesystems toward Baade's window, is inconsistent with and unconfirmed bythe new results. Possible reasons for the large discrepancy arediscussed. They include several observational effects but also apossibility of a genuine increase in the contact-binary density in thecentral parts of the Galaxy. Based on data from the Hipparcos satellitemission and from the David Dunlap Observatory, University of Toronto.
| Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
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