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Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Spectroscopic investigations of classical Cepheids and main-sequence stars in galactic open clusters and associations. II. Open cluster Platais 1 (C2128+488) and small-amplitude Cepheid V1726 Cygni
The small-amplitude Cepheid V1726 Cyg and two membersof open cluster Platais 1 (Platais 1 star No. 1(1921) and Platais 1 star No. 111 (1600))were investigated, using high-resolution CCD spectra. The followingresults were obtained: 1) All objects have the same metallicities, closeto that of the Sun (for V1726 Cyg weighted average [Fe/H]=+0.05, forPlatais 1 star No. 1 (1921) [Fe/H]=+0.13); 2) values of Teffand log g for the B-stars are in excellent agreement with thosedetermined from (B-V) colour indices using a (B-V) ~ (Teff,log g) calibration; 3) the elemental abundances indicate that V1726 Cygis in the post first dredge-up stage with an age near 1.5 x108, and is crossing the Cepheid instability strip for thethird time. Mean values of Teff=6100 K and log g=2.35 +/-0.05 permit us to refine its colour excess to EB-V=0fm 33,which for a distance of d = 1568+/- 13 pc corresponds toMV=-2fm 99. The Cepheid could therefore be pulsating in thefundamental tone, although pulsation in the first overtone is notexcluded; 4) Platais 1 Star No. 1 (1921) is a slowly rotating HgMn-starwith a high helium content, while Platais 1 star No. 111 (1600) is arapidly rotating main-sequence star with a helium content comparable tothat of the Sun; 5) the age of the open cluster is estimated to be about2.5 x 108 yr. Based on the spectra collected with the 6-mtelescope SAO RAS.
| Spectroscopic investigations of classical Cepheids and main-sequence stars in galactic open clusters and associations. I. Association Cas OB2 and the small-amplitude Cepheid SU Cassiopeae
The small-amplitude Cepheid SU Cas and four membersof the association Cas OB2 (HD 16893, HD17327a and b, HD 17443) were investigated,using high-resolution CCD spectra. The following results were obtained:1) All these objects have the same metallicity values, close to that ofthe Sun; 2) Elemental abundance indicates that SU Cas is a post firstdredge-up star with an age from 1 108 to 1.45 108yr, and it is not crossing the Cepheid instability strip for the firsttime. The mean value of log g = 2.35 corresponds to pulsations in thefundamental tone, although errors in gravity estimations provideovertone pulsations. The questions about its pulsational mode andmembership in Cas OB2 remained open; 3) HD17327a is a slowly rotating HgMn-star with the highest heliumcontent among such objects, while HD 16893 also has a manganeseoverabundance and might be classified as an Am-star; 4) HD17327b and HD 17443 are rapidly rotating main-sequence stars,while HD 17443 has a helium content comparable with that of the Sun.
| UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
| A search for hot post-AGB stars in the IRAS Point Source Catalog.
In this paper a first step is made to search for hot post-AGB stars inthe IRAS Point Source Catalog. In order to find objects that evolved offthe AGB a longer time ago than post-AGB objects discussed in theliterature, objects that were not detected at 12 μm by IRAS wereselected, The selection yielded 15 objects, of which 12 have spectraltype B, and would appear to be efficient in finding hot objects.However, this result does not necessarily mean that these are oldevolved objects. Some stars are associated with dense galactic cirrusand are probably normal massive supergiants, and a number of stars aregood post-AGB candidates because of their galactic latitudes and theircool, extended infrared emission. The possibility remains that theseobjects are normal supergiants heating the local interstellar medium.Finally, three remaining objects appear to be genuine post-AGB(candidate) stars, as is attested by their spectral and photometricproperties. The main conclusion derived from modelling their spectralenergy distributions is that the objects evolved off the AGB about 1000years ago, significantly longer than what is found for other post-AGBstars. Emission lines have appeared in the spectrum of one of theseobjects, SAO 243756, over the last 20 years. SAO 243756 bears closeresemblance to other objects that have been proposed to have entered thePlanetary Nebula phase recently. Several aspects of the problem ofselecting post-AGB stars in general are discussed.
| A preliminary compilation of DS-programme star positions
A catalog is presented of the double-star-program (DS-program) starpositions, listing right ascensions for 930 DSs and declinations for1225 DSs of the program. The positions were compiled from the observedvalues obtained between 1980 and 1987 with the meridian circles of sixUSSR observatories (the Moscow, Kazan', Kiev, Khar'kov, Odessa, andTashkent Observatories) and the Belgrade Observatory. The measurementsand the treatment of the observational material were performed using therelative method, and the FK-4 system stars were used as reference stars.
| Radial velocity measurements. IV - Ground-based accompaniment to the HIPPARCOS observation program
The paper presents 396 radial velocities of stars distributed in 19fields of 4 x 4 degrees. The study employs the Fehrenbach objectiveprism method and the same measuring technique used in a previous paper(Fehrenbach et al., 1987).
| Visual multiples. VIII - 1000 MK types
A total of 1000 new classifications are given for stars brighter than B= 8.0 mag in the Aitken double star catalog. The classificationssupplement 865 classifications obtained in 1981 and 1984. Among thenewly discovered stars are 12 new Ap stars, eight Lambda Bootis stars,one Ba II star, and 60 Am stars. A detailed list of the newclassifications is given.
| The local system of early type stars - Spatial extent and kinematics
Published uvby and H-beta photometric data and proper motions arecompiled and analyzed to characterize the structure and kinematics ofthe bright early-type O-A0 stars in the solar vicinity, with a focus onthe Gould belt. The selection and calibration techniques are explained,and the data are presented in extensive tables and graphs and discussedin detail. The Gould belt stars of age less than 20 Myr are shown togive belt inclination 19 deg to the Galactic plane and node-lineorientation in the direction of Galactic rotation, while the symmetricaldistribution about the Galactic plane and kinematic properties (purecircular differential rotation) of the belt stars over 60 Myr oldresemble those of fainter nonbelt stars of all ages. The unresolveddiscrepancy between the expansion observed in the youngest nearby starsand the predictions of simple models of expansion from a point isattributed to the inhomogeneous distribution of interstellar matter.
| Measurements of binary stars performed at Nice (Second series)
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984A&AS...57..467M&db_key=AST
| An investigation of the stellar association containing the 1.95 day Cepheid SU Cassiopeiae
The results of photometric and spectroscopic observations of SU Cas andthe surrounding dust complex are reported. UBV photometry was made ofearly type stars in the dust complex on eight nights in 1978-79 and afurther 10 stars were surveyed within 7 arcmin of SU Cas. Spectroscopicmeasurements were also made of the objects in order to obtain radialvelocities and equivalent widths. The data suggest the region has amoving cluster (BA association) 30 pc in angular extent, with the 1.95arcday Cepheid SU Cas as a member. The association is 255-261 pc distantand has a 6 pc spread between members. The association stars are around120 Myr old, typical of 4 solar mass stars. Finally, the core membersinclude visual and spectroscopic binary system and a short-periodCepheid.
| Radial velocities for early type stars in six galactic regions
Coudespectroscopy has been carried out for 353 stars of spectral typesB0-A0 and V magnitudes between 6.5 and 10.8 m, selected in six regions(three northern and three southern) close to the galactic plane at thegalactic longitudes 135, 175, 315 and 350 deg. The radial velocitieswere obtained by cross-correlating each spectrogram with a referencespectrogram giving an internal error of 1.4 km/s.
| Four-color and H-beta photometry for O-A0 type stars in three regions near the galactic equator
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1982A&AS...49..561W&db_key=AST
| The distance of the Cepheid SU CAS and its pulsation mode
Racine (1968) has used field stars which illuminate reflection nebulaenear SU Cas to determine the distance of the Cepheid. These stars havebeen reobserved in the four-color and H-beta system and found to be atseveral different distances. If SU Cas is associated with one of them,HD 17706, it must be a first-overtone pulsator. However, since thereflection nebulae in the region appear to be mostly unrelated to eachother, the case for overtone pulsation in this star is very weak, andits distance can not be reliably determined in this way.
| Distance of the cepheid SU Cas.
Abstract image available at:http://adsabs.harvard.edu/abs/1968AJ.....73..588R
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