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Observations of OB-stars at the former Leiden Southern Station
About 700 stars, mostly OB-stars, were observed by the author at theformer Leiden Southern Station at Hartebeespoortdam, South Africa, inthe observing seasons 1965, 1968, 1969, 1974, 1977, 1978. Observationswere made in the five channels of the Walraven photometric system. Dueto weathering of the telescope mirror the W channel gave no reliableresults for the faintest stars (m = 11 mag); in these cases the U-Wcolour index is not given. The change in sensitivity in the V channel,supposedly having occurred in 1968, was not recognised. Table~5 is onlyavailable 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/qcat?J/A+A/369/527
| Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
| Properties of the Walraven VBLUW photometric system
The Walraven five-channel (VBLUW) photometer has been used primarily tostudy Cepheids and RR Lyrae variables. Those properties of the VBLUWphotometric system are discussed which are important for analyzing andinterpreting data on such stars. The standard stars that define thesystem are examined, the long-term stability of these stars is examined,and the responses of the photometric passbands are analyzed. Correctionsfor atmospheric extinction and interstellar reddening are reviewed,noting that color terms in the extinction corrections are sufficientlysmall to be neglected and that nonlinear terms in reddening correctionscan also be neglected provided the reddening is not higher than about1.25 magnitudes. Application of the VBLUW system to the classificationof A, F, and G stars, Hyades main-sequence stars, bright field stars,and subdwarfs is demonstrated, and observed two-color diagrams arecompared with theoretical diagrams based on model atmospheres. It isconcluded that a three-dimensional classification based on effectivetemperature, surface gravity, and heavy-element abundance is possiblefor A, F, and G spectral types and that VBLUW photometry is more thantwice as sensitive as Stroemgren uvby photometry to differences inheavy-element abundances below 8000 K.
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | בתולה |
| התרוממות ימנית: | 14h10m47.75s |
| סירוב: | +00°47'58.5" |
| גודל גלוי: | 6.859 |
| מרחק: | 92.937 פארסק |
| תנועה נכונה: | -43.8 |
| תנועה נכונה: | -33.5 |
| B-T magnitude: | 7.039 |
| V-T magnitude: | 6.874 |
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