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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.
| 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.
| New proper motion determination of Luyten catalogue stars (LTT) south of declination -40 degrees and right ascension between 00 H and 04 H 30 M
Data are given for 104 LTT stars found on 11 areas, covering 25 squaresdegrees each, south of declination -40 degrees and right ascensionbetween 00 h and 04 h 30 m. Three stars present differences in propermotion greater than 0.10 arcsec, six present differences in positionangle greater than 20 degrees and one presents those differences in bothvalues.
| Measures of southern visual double stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977PASP...89..588H&db_key=AST
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Observation and Astrometry data
| Constellation: | Ύδρος |
| Right ascension: | 01h26m09.45s |
| Declination: | -67°50'33.0" |
| Apparent magnitude: | 8.727 |
| Distance: | 66.007 parsecs |
| Proper motion RA: | 117 |
| Proper motion Dec: | -61.9 |
| B-T magnitude: | 9.692 |
| V-T magnitude: | 8.807 |
Catalogs and designations:
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