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Stellar uvbybeta photometry in three EUV shadow directions
We present the uvbybeta data used to locate the dust and derivedistances for nearby diffuse interstellar clouds in the EUV shadowslb27-31, lb165-32 and lb329+46 discovered by the Extreme UltravioletExplorer. The photometrically derived parallaxes of our program starsare compared to the parallaxes listed in the Hipparcos Catalog. Withinthe photometric distance limit of 150 pc, the photometric parallaxes of21 ``normal" stars are consistent with the Hipparcos measurements withinan uncertainty of 15%. Much as expected for the Str{ömgren system.Since all program stars are brighter than V~11.5 most of them areincluded in the Tycho photometry. For our sample of ~ 200 stars we findVby and V_T to be consistent. Few stars are common topublished uvbybeta catalogs, ~ 10, V and the indices compare well apartfrom beta where a zero point difference of 11 mmag is noticed.Tables \ref{tab1}-\ref{tab3} are also available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.htmlBased on observations at the European Southern Observatory, La Silla,Chile.
| Spectral classifications in the near infrared of stars with composite spectra. II. Study of a sample of 180 stars
A sample of 180 supposedly composite-spectrum stars has been studied onthe basis of spectra obtained in the near infrared (8370-8780 Angstroms)at a dispersion of 33 Anstroms/mm. The objective was to study the coolercomponents of the systems. Of our sample, 120 are true compositespectra, 35 are hot spectra of types B, F and 25 are Am stars. We find astrong concentration of the cooler components of the composite spectraaround G8III. In view of the difficulty of classifying compositespectra, because of the super position of an early type dwarf and a latetype giant or supergiant spectrum, we have made several tests to controlthe classification based upon the infrared region. Since all tests gavepositive results, we conclude that our classifications can be consideredas being both reliable and homogeneous. Table \ref{tab1} is alsoavailable electronically at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstracts.html} Based upon observationscarried out at Observatoire de Haute-Provence (CNRS).
| CCD astrometry and instrumental Delta-V photometry of wide visual double stars. III - Differential measurements of often observed southern pairs
We present accurate relative positions and instrumental visual (BesselV) magnitude differences of southern wide star components. The meanaccuracy of the angular separation is 0.02 arcsecs, which corresponds to1.5 micron on the CCD chip, and of magnitude difference 0.007mag/exposure. The program pairs are targets of the HIPPARCOS mission andthey have been observed at least four times in the last 150 yrs.
| CCD measurements of visual binaries
CCD measurements of visual double stars were obtained with the ESO 1.5 mdanish reflector. All binaries observed are candidates for the HIPPARCOSInput Catalogue. More than 400 observations have been made in four clearnights. The accuracy obtained is comparable to the accuracy of thephotographic technique, but the observing and reduction times are oneorder of magnitude smaller.
| Visual multiples. VII - MK classifications
Classifications are given for 865 components of visual multiples; theyshow no systematic differences from the MK system, and the random errorsare one subclass in type and two-thirds of a luminosity class. It isfound that at least 1% of the F-type IV and V stars are weak-lined, 32%of the A4-F1 IV and V stars are Am, and 5% of the A0-A3 IV and V starsare early-type Am. Attention is called to the large fraction (55%) ofthe A3-A9 III-V stars that are of luminosity classes III or IV, unlikethe percentage (16%) at neighboring types.
| Composite spectrum stars susceptible to lunar occultation
The use of lunar occultations to detect close double stars has becomeroutine practice. Since a number of composite spectrum stars havealready been noted as double by occultation observers, an additionallist, complementary to those of Herr, of potential occultation doublesshould be useful. To this end, the paper examines the stars from fivegeneral studies of composites for their susceptibility to lunaroccultation. An identification list of 68 composite spectrum starssusceptible to lunar occultation is presented. Predicted times offavorable occultation events are given for several of the faintercandidates.
| A study of visual binaries having primaries above the main sequence.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960AJ.....65...60S&db_key=AST
| A survey of stars with composite spectra.
Not Available
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | בתולה |
| התרוממות ימנית: | 14h05m57.48s |
| סירוב: | -13°04'11.8" |
| גודל גלוי: | 9.766 |
| תנועה נכונה: | -30.2 |
| תנועה נכונה: | -12 |
| B-T magnitude: | 10.333 |
| V-T magnitude: | 9.813 |
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