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Orbit of the Spectroscopic Binary HD 107346 Containing a Very Hot Component
The orbit of the spectroscopic binary system HD 107346 is calculatedfrom 50 CORAVEL-type radial velocity measurements. An orbit with aperiod P = 1024.2 days is obtained. The spectral type of the primary, G8IV, has been estimated from the spectrum analyzed by Straižys(1984). The spectral type and absolute magnitude of the secondary, sdO,is estimated by modeling the spectral energy distribution of the binaryconstructed from measurements in the FAUST, GALEX, UBV, Vilnius, ICousins and JHK photometric systems. The subdwarf component of thebinary system exhibits a very high temperature. We do not exclude thatthe hot component is a close interacting binary.
| Classification of Population II Stars in the Vilnius Photometric System. II. Results
The results of photometric classification of 848 true and suspectedPopulation II stars, some of which were found to belong to Population I,are presented. The stars were classified using a new calibrationdescribed in Paper I (Bartkevicius & Lazauskaite 1996). We combinethese results with our results from Paper I and discuss in greaterdetail the following groups of stars: UU Herculis-type stars and otherhigh-galactic-latitude supergiants, field red horizontal-branch stars,metal-deficient visual binaries, metal-deficient subgiants, stars fromthe Catalogue of Metal-deficient F--M Stars Classified Photometrically(MDPH; Bartkevicius 1993) and stars from one of the HIPPARCOS programs(Bartkevicius 1994a). It is confirmed that high galactic latitudesupergiants from the Bartaya (1979) catalog are giants or even dwarfs.Some stars, identified by Rose (1985) and Tautvaisiene (1996a) as fieldRHB stars, appear to be ordinary giants according to our classification.Some of the visual binaries studied can be considered as physical pairs.Quite a large fraction of stars from the MDPH catalog are found to havesolar metallicity. A number of new possible UU Herculis-type stars, RHBstars and metal-deficient subgiants are identified.
| FAUST Observations of Ultraviolet Sources toward the Virgo Cluster
We analyze three UV images covering a ~100 square degree field towardthe Virgo cluster, obtained by the FAUST space experiment. We detect 191sources to a signal-to-noise ratio of 4.4 and identify 94% of them. Mostsources have optical counterparts in existing catalogs, and about halfare identified as galaxies. Some sources with no listed counterpart wereobserved at the Wise Observatory. We present the results oflow-resolution visible spectrophotometry and discuss the foreground 101stellar sources and the 76 detected galaxies, both in the cluster and inthe foreground or background. We derive conclusions on star formationproperties of galaxies and on the total UV flux from discrete anddiffuse sources in the cluster. We test for the presence of intraclusterdust, determine the clustering properties of UV emitting galaxies, andderive the UV luminosity function of Virgo galaxies.
| A catalog of far-ultraviolet point sources detected with the fast FAUST Telescope on ATLAS-1
We list the photometric measurements of point sources made by the FarUltraviolet Space Telescope (FAUST) when it flew on the ATLAS-1 spaceshuttle mission. The list contains 4698 Galactic and extragalacticobjects detected in 22 wide-field images of the sky. At the locationssurveyed, this catalog reaches a limiting magnitude approximately afactor of 10 fainter than the previous UV all-sky survey, TDl. Thecatalog limit is approximately 1 x 10-14 ergs A sq cm/s,although it is not complete to this level. We list for each object theposition, FUV flux, the error in flux, and where possible anidentification from catalogs of nearby stars and galaxies. Thesecatalogs include the Michigan HD (MHD) and HD, SAO, the HIPPARCOS InputCatalog, the Position and Proper Motion Catalog, the TD1 Catalog, theMcCook and Sion Catalog of white dwarfs, and the RC3 Catalog ofGalaxies. We identify 2239 FAUST sources with objects in the stellarcatalogs and 172 with galaxies in the RC3 catalog. We estimate thenumber of sources with incorrect identifications to be less than 2%.
| Progress report on the radial velocity measurement programme of population II stars.
Not Available
| Radial velocities of Population II stars. I
Radial velocity measurements are presented for 81 Population II stars.The sample comprises components of metal-poor binary stars,spectroscopic binary candidates, high latitude supergiants,metal-deficient stars with spectroscopic determinations of Fe/H,HIPPARCOS program stars, and some other stars of metal-poor population.The radial velocity measurements were made in February 1988 with aphotoelectric stellar velocimeter.
| A first catalogue of speckle-interferometric measurements of binary stars made with 6-m telescope of the USSR AS.
Not Available
| Calcium abundances in atmospheres of 43 G and K giants
Not Available
| Digital speckle interferometry of 72 binary stars
Position angles and separations have successfully been measured for 72double stars with a digital speckle interferometer on the 6-m telescope.In both Theta and rho the internal measurement error is about 0.003 ofarc mins. The small residuals from published orbits indicate thatappreciable systematic effects are abent. In addition, 43 other starswere unresolved at the epochs specified.
| HD 107346, a red subgiant with a strong ultraviolet excess
Spectral scans of the celestial object HD 107346 were carried out in the3870-4540 A range on May 9-10, 1982 to study observed V and UVenhancement. The data indicated that the object is approximately a G8star. Combining the new data with previous observations yielded a meanenergy distribution in the V band which was compared with typical G5 IV,G8 IV, and K0 IV stars. Observed anomalies indicate that HD 107346 is abinary system. Synthesis of color indices for the object revealed thepresence of a hot component. Subsequent spectroscopy in March-June 1983failed to resolve the binary components. Further scans at EUVwavelengths are recommended.
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Osservazione e dati astrometrici
| Costellazione: | Vergine |
| Ascensione retta: | 12h20m27.63s |
| Declinazione: | +09°59'23.7" |
| Magnitudine apparente: | 10.34 |
| Moto proprio RA: | -19.5 |
| Moto proprio Dec: | -10.7 |
| B-T magnitude: | 11.417 |
| V-T magnitude: | 10.429 |
Cataloghi e designazioni:
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