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ICCD Speckle Observations of Binary Stars.XV.An Investigation of Lunar Occultation Systems
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....112.2260M&db_key=AST
| A homogeneous catalog of new UBV and H-beta photometry of B- and A-type stars in and around the Scorpius-Centaurus OB association
B- and A-type stars in and near the Sco-Cen OB association areinvestigated with UBV and H-beta photometry to acquire data relevant tothe luminosity function of Sco-Cen. The measurements generally consistof two 10-s integrations of U, B, V, (W, N) filters, and theobservations are corrected iteratively for atmospheric extinction andinstrumental response. The data presented give the mean V magnitude,mean B-V, mean U-B, and the estimated uncertainties for these values.The catalog provides a homogeneous catalog of data for a large fieldwith stellar objects delineating membership to the association Sco-Cenand that affect the luminosity function of the aggregate.
| Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
| Physical parameters of stars in the Scorpio-Centaurus OB association
Walraven photometry is presented of established and probable members ofthe Scorpio-Centaurus OB association. For each star, effectivetemperature and surface gravity are derived using Kurucz (1979)atmosphere models. From the Straizys and Kuriliene (1981) tables,absolute magnitudes are calculated. Distance moduli and visualextinctions are determined for all stars. From a comparison of theHR-diagrams of the stars in each subgroup with theoretical isochrones,the ages of the three subgroups are derived. The distances to the threesubgroups are shown to be different; there is a general trend (alsowithin each subgroup) for the distances to be larger at higher galacticlongitudes. The visual extinction in the youngest subgroupUpper-Scorpius, is well correlated with the IRAS 100-micron map. Thedistance toward the Ophiuchus dark clouds is found to be 125 pc, basedon the photometric distances to the stars. Most of the early-type starsin Upper-Scorpius are located at the far side of the dark clouds.
| The velocity field of the outer Galaxy in the southern hemisphere. III - Determination of distances to O, B, and A type stars in the Walraven photometric system
The Walraven photometric system has been used to derive distances tostars of spectral types earlier than A7. The details of the observingprocedure are given, and the way the data were analyzed is described.The accuracy of the data is discussed, and the results are compared withthose of Gathier et al. (1986). The observational results for stars ineight well-studied star cluster are presented, compared with theliterature, and discussed.
| Photoelectric observations of lunar occultations. XIV
Observations of 314 events between March 1982 and March 1983 arepresented in the same form as in previous papers in this series. Theresults include 18 cases of duplicity of which 12 appear to be newdiscoveries. Unluckily, few cases of possible large angular diametersoccurred, and in no case can the results derived be accepted withoutreserve, these having been observed at very low altitudes withconsequent severe corruption by seeing effects. A remark on theincidence of doubles in the Hyades and its possible consequences forestimates of stellar distances is appended.
| An ultraviolet extinction study of the rho Ophiuchi dark cloud
Five-band ultraviolet spectrophotometry has been carried out for 54stars in the upper Scorpius complex. Of these, 14 stars in the rhoOphiuchi dark cloud and 13 in the surrounding area are found to be freeof spectral peculiarities and contamination by scattered light fromnearby bright stars. The dark cloud stars give extinction curves whichare significantly lower than the average extinction curves derived byother investigators and also those observed for localized regions suchas the area around Cygnus X-1 and the Cepheus OB III cluster. Thisimplies that the dust in the upper Scorpius region, especially that inthe rho Ophiuchi dark cloud has larger average size than the normalinterstellar medium. R, the ratio of total-to-selective extinction, isfound to be 4.2. The effects of a lower extinction curve on thechemistry of a dark cloud is also briefly discussed.
| Some Characteristics of the B and A Stars in the Upper Scorpius Complex
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1967ApJ...147.1003G&db_key=AST
| A Study of the II Scorpii Asscoiation.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961ApJ...133..843H&db_key=AST
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| Сазвежђа: | Змијоносац |
| Ректацензија: | 16h42m17.41s |
| Deклинација: | -20°11'13.3" |
| Apparent магнитуда: | 8.637 |
| Даљина: | 10000000 parsecs |
| Proper motion RA: | 0 |
| Proper motion Dec: | 0.3 |
| B-T magnitude: | 8.768 |
| V-T magnitude: | 8.648 |
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