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Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 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
| Micrometer measurements of double stars made at the Côte D'Azur and Calar Alto observatories
We report 312 micrometer measurements of 155 visual double stars madewith the 50 cm refractor at the Côte D'Azur observatory (Nice,France) and with the 152 cm telescope at Calar Alto observatory(Almería, Spain).
| 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 ages and dimensions of Trapezium systems
MK spectral types and memberships were obtained for 120 stars in 31systems thought to be Trapezium systems. Twenty-eight optical componentswere found, after the removal of which, 17 systems are hierarchical andthree have no companions. Practically all of the remaining Trapeziumsystems are either the same age or younger than the Hyades, i.e., lessthan 10 to the 8.9th years old. The maximum radii of Trapezium combinedwith hierarchical systems exhibit a dramatic decrease with primaryspectral type or age T, ranging from about 50,000 AU for OB primaries to1000 AU for G dwarfs. If stars have an observed binary separation ofabout 5000 AU, it is unlikely that the sun would have a stellarcompanion at 92,000 AU. A Ba II star with a physical companion, a starwith strong double Ca II emission lines, and a chance projection of anearby quadruple hierarchical system on a distant triple hierarchicalsystem is discussed.
| Optical observations of ultraviolet objects. II - Classification and photometry /l = 0 to 145 deg/
UBV photometry and MK spectral classification are presented for a sampleof stars originally selected as UV objects from satellite photometrywith the S2/68 experiment. Although most stars of the sample arespectroscopically normal, a number of hot, subluminous stars were alsofound. Radial velocities are given for some of the stars observed. It isproposed that the majority of the apparently normal early B stars athigh galactic latitudes which are not runaway stars are subluminousdisc-population analogues of horizontal branch B stars of Population II.
| Mesures d'etoiles doubles a Meudon (3eme et derniere serie).
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976A&AS...23..205M&db_key=AST
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