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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
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| Intermediate and narrow band photometry of newly discovered CP 2 stars
From Bidelman's list (1983) of northern stars of astrophysical interesteleven chemically peculiar early type (CP2) stars were photometricallyinvestigated to check the reported CP2 character by means of the Delta-aphotometry and to obtain Stroemgren and H-beta values. The CP2 characterof all stars is verified, in one case the star belongs to a hottersubgroup than reported. One star (BD + 24 deg 3675) turns out to bevariable and shows the largest Delta-a value ever measured. Besidesthis, two stars from the Bright Star Catalogue were found to be CP2stars.
| Objective-prism discoveries in the northern sky. I
Attention is given to 175 northern hemisphere stars whose newlyrecognized peculiar, or otherwise prepossessing characteristics havebeen noted in a preliminary inspection of moderate dispersion objectiveprism plates. The plates were obtained with a 10-deg prism. The starlist gives HD or BD, alpha and delta values, magnitude, and type.
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | הרקולס |
| התרוממות ימנית: | 18h43m51.20s |
| סירוב: | +24°04'52.3" |
| גודל גלוי: | 9.333 |
| תנועה נכונה: | 2.6 |
| תנועה נכונה: | 0.4 |
| B-T magnitude: | 9.374 |
| V-T magnitude: | 9.337 |
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