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Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Stars Classified as Constant in the General Catalogue of Variable Stars, II
Photometric observations have been made of 36 stars classified as CST orCST: in the General Catalogue of Variable Stars. Six of these stars arefound to vary and three others were deemed possible variables. Of thecertain variables, two (MR Her and TY Sge) are red pulsators, one (V1585Cyg) is a rapid irregular variable, one is apparently a short periodCepheid-strip star (V432 Oph), one is an eclipsing binary (AQ Boo) andone is uncertain type (V351 Cyg). The stars we have observed as MR Herand TY Sge are the same ones which were identified on finding charts inthe discovery papers suggesting that these stars have intervals ofvariability and intervals of quiescence. V432 Oph is of special interestbecause our photometry indicates that it may be either a double modeCepheid or a peculiar long period RR Lyrae star depending on which of acouple of possible periods turns out to be correct. (SECTION: Stars)
| Interstellar extinction in the vicinity of the North America and Pelican Nebulae. II
The results of photoelectric photometry of 564 stars in the Vilniusseven-color system in three areas near the North America and PelicanNebulae are given. Photometric spectral types, absolute magnitudes,color excesses, interstellar extinction,s and distances to the stars aredetermined. We find that the dark cloud separating both nebulae is at580 pc distance. A number of stars immersed in the dark cloud have beenfound. It seems that the dark cloud extends south down to 40 degdeclination. The area southwest of alpha Cygni in the declination zones42 deg and 43 deg is comparatively transparent at least up to 1 kpc.
| Radial velocity measurements. II - Ground-based observations of the program stars for the HIPPARCOS satellite
New radial velocities for 446 stars of magnitude 9.0 or brighter in 1616-sq-deg fields of the Northern Hemisphere are determined by automaticPDS measurement of 80-A/mm-dispersion spectra obtained at theObservatoire de Haute Provence using a 17-cm-diameter objective prism.The fields were selected to provide data for the input catalog of theESA Hipparcos astrometric satellite. The measurement techniques andprecision are discussed, and the results are presented in extensivetables and graphs.
| The S201 far-ultraviolet imaging survey. II - A field in Cygnus
Far-ultraviolet imagery of a region in Cygnus, a 20 deg diameter fieldcentered near (1950) R. A. 21 h 31.2 m decl. +37 deg 25 arcmin, wasobtained by the S201 far-ultraviolet camera during the Apollo 16mission. In a 10 minute exposure covering the 1250-1600 A wavelengthrange (effective wavelength 1400 A), 730 star images can be detected,corresponding to a limiting ultraviolet magnitude of about m (1400) =10. Assuming nominal interstellar extinction values in this region nearthe galactic plane, this result corresponds to the detection of A0 Vstars to a distance of 300 pc and of B0 V stars to 1500 pc.Uncertainties in spectral classification and interstellar extinction forindividual objects are probably more significant than calibration ormeasurement errors. Most of the objects detected are identified withstars in the Smithsonian Astrophysical Observatory Star Catalog (1966),or the Catalog of Stellar Identifications (1979) or both, but 87 objectsremain unidentified (or are identified with late-type stars).
| Ultraviolet spectroscopy of the outer layers of stars
Ultraviolet observations of the extended atmospheres and circumstellarenvelopes of early-type and cool stars are reviewed. UV spectra of OBstars have shown that mass loss occurs in virtually all these stars andin many Be stars, and the Copernicus satellite has also providedinformation on the physical conditions and variability of the winds. Thewinds have been interpreted in terms of hot coronal wind models,imperfect flow models and radiation pressure models, and estimates ofmass loss ranging from 10 to the -10th to 9 x 10 to the -6th solarmasses/year have been obtained. Further UV data of faint stars,additional wavelengths and time variability are required. Recent UV andX-ray experiments have detected stellar chromospheres, transitionregions coronas and winds in cool stars. Semiempirical line-profile andline-flux models and purely theoretical atmospheric models have beenconstructed to explain chromosphere, corona and wind data, and futureobservations of the physical properties of stellar chromospheres,coronas and winds, terms in the energy balance equation, stellaractivity and its long-term variability and atmospheric modifications dueto the presence of companion stars are proposed for such missions asSpacelab.
| The Cepheid Variable S. Sagittae. I. The Radial-Velocity Variation.
Abstract image available at:http://adsabs.harvard.edu/abs/1952ApJ...116..348H
| Mitteilungen über veränderliche und verdächtige Sterne
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| Stars having peculiar spectra.
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