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The HR-diagram from HIPPARCOS data. Absolute magnitudes and kinematics of BP - AP stars
The HR-diagram of about 1000 Bp - Ap stars in the solar neighbourhoodhas been constructed using astrometric data from Hipparcos satellite aswell as photometric and radial velocity data. The LM method\cite{luri95,luri96} allows the use of proper motion and radial velocitydata in addition to the trigonometric parallaxes to obtain luminositycalibrations and improved distances estimates. Six types of Bp - Apstars have been examined: He-rich, He-weak, HgMn, Si, Si+ and SrCrEu.Most Bp - Ap stars lie on the main sequence occupying the whole width ofit (about 2 mag), just like normal stars in the same range of spectraltypes. Their kinematic behaviour is typical of thin disk stars youngerthan about 1 Gyr. A few stars found to be high above the galactic planeor to have a high velocity are briefly discussed. Based on data from theESA Hipparcos astrometry satellite and photometric data collected in theGeneva system at ESO, La Silla (Chile) and at Jungfraujoch andGornergrat Observatories (Switzerland). Tables 3 and 4 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Far-Ultraviolet Stellar Photometry: Fields Centered on rho Ophiuchi and the Galactic Center
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..104..101S&db_key=AST
| UBV light curves of V356 Sagittarii
We report here UBV observations of the unusual eclipsing binary V356Sagittarii from 1973, 1974, and 1975. Although there are phase gaps,light-curve form and absolute level differ only slightly from lightcurves of 23 years earlier in the phases that are covered. Scatter isanomalously large, as in the earlier observations, and seems to bediagnostic of some intrinsic abnormality.
| Far-ultraviolet stellar photometry: Fields in Sagittarius and Scorpius
Far-ultraviolet photometry for 741 objects in a field in Sagittariuscentered near M8 and 541 objects in a field centered near sigma Scorpiiis presented. These data were extracted from electographic imagesobtained with two cameras during a shuttle flight in 1991 April/May. Thecameras provided band passes with lambdaeff = 1375 A andlambdaeff = 1781 A. Synthetic colors show that these bandsare sensitive to effective temperature for hot stars. Our measurementswere placed on a quantitative far-ultraviolet magnitude scale byconvolving the spectra of stars observed by IUE with our cameras'spectral response functions. Fifty-eight percent of the ultravioletobjects were identified with visible stars using the SIMBAD databasewhile another 40% of the objects are blends of early type stars tooclose together to separate with our resolution. Our photometry iscompared with that from the TD-1, OAO 2, and ANS satellites and the S201(Apollo 16) far-ultraviolet camera and found to agree at the level of afew tenths of a magnitude. Unlike previous studies, almost half of theidentified visual counterparts to the ultraviolet objects are early Bstars. A plot of distance modulus against ultraviolet color excessreveals a significant population of stars with strong ultravioletexcess.
| Occultations of stars by solar system objects. IX - Occultations of catalog stars by steroids, planets, and major satellites in 1992 and 1993
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1992AJ....103.2079W&db_key=AST
| A Recent Time of Minimum for V356-SAGITTARIUS
A fragmentary light curve based on photometric observations obtained in1979 yields a mid point for primary eclipse of JD(hel.)=2444158.027.This indicates that the orbital period is not undergoing any changelarge enough to be measurable at this time.
| Spectrophotometry of massive eclipsing binary stars
Normalized flux distributions have been measured for U Oph, AG Per,Lambda Tau, and V356 Sgr. Light curves at 4700 A for U Oph and AG Perare used to check published eclipsing-binary-system parameters, and theparameters given by Koch and Koegler (1977) and Popper (1974) areemployed for the analysis of U Oph and AG Per, respectively. No evidenceof circumstellar matter is found for U Oph and AG Per. The resultsindicate that the spectra of Lambda Tau from phase 0.77 to 0.90 arecharacteristic of spectral type B4, that the spectra of V356 Sgr matchB3 and A0 spectra except at isolated phases exhibiting UV excess light,and that the excess-light spectrum is characteristic of hydrogenfree-bound emission. Color excesses and component-star temperatures andabsolute visual magnitudes are determined for U Oph and AG Per.
| Photoelectric Observations of Eclipsing Binaries.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1957ApJS....3..107P&db_key=AST
| The Eclipsing Binary V356 Sagittarii.
Abstract image available at:http://adsabs.harvard.edu/abs/1955ApJ...121...56P
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Osservazione e dati astrometrici
| Costellazione: | Sagittario |
| Ascensione retta: | 18h42m25.44s |
| Declinazione: | -20°18'43.0" |
| Magnitudine apparente: | 7.12 |
| Distanza: | 505.051 parsec |
| Moto proprio RA: | -4.9 |
| Moto proprio Dec: | -9.8 |
| B-T magnitude: | 7.313 |
| V-T magnitude: | 7.136 |
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