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|Sixth Catalogue of Fundamental Stars (FK6). Part III. Additional fundamental stars with direct solutions|
The FK6 is a suitable combination of the results of the HIPPARCOSastrometry satellite with ground-based data, measured over a longinterval of time and summarized mainly in the FK5. Part III of the FK6(abbreviated FK6(III)) contains additional fundamental stars with directsolutions. Such direct solutions are appropriate for single stars or forobjects which can be treated like single stars. Part III of the FK6contains in total 3272 stars. Their ground-based data stem from thebright extension of the FK5 (735 stars), from the catalogue of remainingSup stars (RSup, 732 stars), and from the faint extension of the FK5(1805 stars). From the 3272 stars in Part III, we have selected 1928objects as "astrometrically excellent stars", since their instantaneousproper motions and their mean (time-averaged) ones do not differsignificantly. Hence most of the astrometrically excellent stars arewell-behaving "single-star candidates" with good astrometric data. Thesestars are most suited for high-precision astrometry. On the other hand,354 of the stars in Part III are Δμ binaries in the sense ofWielen et al. (1999). Many of them are newly discovered probablebinaries with no other hitherto known indication of binarity. The FK6gives, besides the classical "single-star mode" solutions (SI mode),other solutions which take into account the fact that hidden astrometricbinaries among "apparently single-stars" introduce sizable "cosmicerrors" into the quasi-instantaneously measured HIPPARCOS proper motionsand positions. The FK6 gives, in addition to the SI mode, the "long-termprediction (LTP) mode" and the "short-term prediction (STP) mode". TheseLTP and STP modes are on average the most precise solutions forapparently single stars, depending on the epoch difference with respectto the HIPPARCOS epoch of about 1991. The typical mean error of anFK6(III) proper motion in the single-star mode is 0.59 mas/year. This isa factor of 1.34 better than the typical HIPPARCOS errors for thesestars of 0.79 mas/year. In the long-term prediction mode, in whichcosmic errors are taken into account, the FK6(III) proper motions have atypical mean error of 0.93 mas/year, which is by a factor of about 2better than the corresponding error for the HIPPARCOS values of 1.83mas/year (cosmic errors included).
|Search for young stars among ROSAT All-Sky Survey X-ray sources in and around the R CrA dark cloud|
We present the ROSAT All-Sky Survey data in a 126 deg2 areain and around the CrA star forming region. With low-resolutionspectroscopy of unidentified ROSAT sources we could find 19 new pre-mainsequence stars, two of which are classical T Tauri stars, the othersbeing weak-lined. The spectral types of these new T Tauri stars rangefrom F7 to M6. The two new classical T Tauri stars are located towardstwo small cloud-lets outside of the main CrA cloud. They appear to be ~10 Myrs old, by comparing their location in the H-R diagram withisochrones for an assumed distance of 130 pc, the distance of the mainCrA dark cloud. The new off-cloud weak-line T Tauri stars may haveformed in similar cloudlets, which have dispersed recently.High-resolution spectra of our new T Tauri stars show that they havesignificantly more lithium absorption than zero-age main-sequence starsof the same spectral type, so that they are indeed young. From thosespectra we also obtained rotational and radial velocities. For somestars we found the proper motion in published catalogs. The directionand velocity of the 3D space motion - south relative to the galaticplane - of the CrA T Tauri stars is consistent with the dark cloud beingformed originally by a high-velocity cloud impact onto the galacticplane, which triggered the star formation in CrA. We also present VRIJHKphotometry for most of the new T Tauri stars to derive theirluminosities, ages, and masses. Partly based on observations collectedat the 1.52 m and 3.5 m telescopes of the European Southern Observatory,Chile, in programs 55.E-0549, 57.E-0646, and 63.L-0023, and onobservations collected at the 0.9 m, 1.5 m, and 4.0 m CTIO telescope.
|The ROSAT all-sky survey catalogue of optically bright late-type giants and supergiants|
We present X-ray data for all late-type (A, F, G, K, M) giants andsupergiants (luminosity classes I to III-IV) listed in the Bright StarCatalogue that have been detected in the ROSAT all-sky survey.Altogether, our catalogue contains 450 entries of X-ray emitting evolvedlate-type stars, which corresponds to an average detection rate of about11.7 percent. The selection of the sample stars, the data analysis, thecriteria for an accepted match between star and X-ray source, and thedetermination of X-ray fluxes are described. Catalogue only available atCDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
|Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.|
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
|The position corrections of 1400 stars observed with PA II in San Juan.|
|Second astrolabe catalogue of Santiago.|
Positions for 350 FK5 and 164 FK5 Extension stars as determined with theDanjon astrolabe of Santiago and differences astrolabe-catalogue aregiven for Equinox J2000.0 and for the mean observation epoch of eachstar. The average mean error in alpha is +/-0.005s and +/-0.07" indelta. The mean epoch of observation of the catalogue is J1979.96.
|Improved Mean Positions and Proper Motions for the 995 FK4 Sup Stars not Included in the FK5 Extension|
|Uvby-Beta Photometry of Equatorial and Southern Bright Stars - Part Two|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&AS...42..311H&db_key=AST
|The radial velocities of 60 southern stars.|
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|Proper motion RA:||25.4|
|Proper motion Dec:||-16.7|
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