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Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
| Late A-type stars: new Strömgren photometric calibrations of absolute magnitudes from HIPPARCOS
Hipparcos trigonometric parallaxes have been used to derive aphotometric absolute magnitude calibration of main-sequence late A-typestars in terms of Strömgren photometric indices - accounting fortemperature, evolution and metallicity effects - and projectedequatorial rotational velocities. The derived calibrations are valid formain-sequence normal A3-A9 and metallic Am stars, showing residuals of0.22 and 0.20 magnitudes, respectively. One of the fitting methods used(BCES) allows the derivation of the observational ZAMS in this spectralrange, showing an excellent accordance with theoretical evolutionarymodels. The evolutionary state of the Am stars is also discussed.Table~A1 is only available in electronic form from CDS via anonymous ftp130.79.128.5, and by e-mail: request to cesca@am.ub.es
| Spectroscopic tests of photoelectric stellar classification of abnormal stars
Spectroscopic classification is obtained for 169 northern A5-G0 starspredicted by Olsen (1979, 1980) to have abnormal spectra on the basis ofStromgren four-color photometry. The success in identifying reddenedearly type stars was nearly 100 percent, for Am and early type weaklined stars about 75 percent, for stars above main sequence about 50percent, for composite spectra about 25 percent, and for Ap and LambdaBoo stars 0 percent. Thus photoelectric photometry is a successful firststep in discovering stars of the more extreme spectroscopicabnormalities.
| Estimation of spectral classifications for bright northern stars with interesting Stromgren indices
The purpose of this investigation is to provide spectroscopic observerswith finding lists of potentially interesting objects. From anunpublished UVBY catalogue of 7026 northern stars (mostly brighter than8.3m) 1094 objects with interesting combinations of UVBY indices havebeen selected. Most stars with post-HD classifications have beenexcluded, as well as late F dwarfs belonging to the intermediatepopulation II. For the 792 remaining stars estimated spectralclassifications are given. The techniques and experience from a previouspaper dealing with southern stars have been utilized here. Among thepredicted spectral classifications are 40 OB stars; 262 Ap, Am, or Fmstars; 16 supergiants of types A to G; 110 bright giants of types A to K(class II); 156 double stars or objects with composite spectra; 26 lateF dwarfs; 91 weak-lined dwarf and giant stars of types F to K, includingearly F-type population II field blue stragglers; and a few possiblefield horizontal branch stars, lambda Bootis-type stars, and late-typehalo giants.
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | דרקון |
| התרוממות ימנית: | 17h44m16.39s |
| סירוב: | +51°47'12.8" |
| גודל גלוי: | 8.391 |
| מרחק: | 137.174 פארסק |
| תנועה נכונה: | 3.1 |
| תנועה נכונה: | -32.2 |
| B-T magnitude: | 8.777 |
| V-T magnitude: | 8.423 |
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