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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).
| Near infrared low-resolution spectra of 7 Be stars and AG CAR
We present and discuss lambda 6470-8780 spectra of 7 poorly-studied Bestars and of one Luminous Blue Variable (AG Car), and give equivalentwidths and radial velocities of selected spectral lines. Based onobservations obtained at Las Campanas Observatory and at the EuropeanSouthern Observatory in Chile
| Improved Mean Positions and Proper Motions for the 995 FK4 Sup Stars not Included in the FK5 Extension
Not Available
| The 5780 diffuse band in peculiar interstellar clouds
This paper presents the spectra of a sample of galactic stars in whichthe broad diffuse interstellar band at 5780 A is strongly attenuated inrelation to their color excess and the neighhor feature at 5797 A isabsent. The unusually large width of the 5780 band which is found in thedirection of the Orion Trapezium stars is discussed in terms ofintrinsic and Doppler broadening. The same clouds (apparently fragmentsof the Orion parent cloud) are known to produce peculiar extinction. Itis suggested that the high density of collapsing clouds facilitatessticking of the diffuse band carriers to grain surfaces where they loosetheir identity reacting with the bulk of grain material. The process ofsticking also alters the optical properties of grains.
| Diffuse bands and peculiar interstellar clouds
An approach to the study of the diffuse interstellar bands (DIBs) isdiscussed, and results obtained so far are presented. Emphasis is placedon lines of sight along which some components of the interstellar mediumincluding the DIBs deviate from the average behavior. The varyingintensity ratios between features belonging to different families, thelack of some of the diffuse bands along peculiar lines of sight, and theapparent absence of DIBs when the reddening is mainly due tocircumstellar matter are considered.
| UBVRI photometry of FK4 and FK4 supplement stars
Photometric UBVRI observations of 172 Southern Hemisphere stars of theFK4 and FK4-Supplement catalogs, obtained using a dry-ice-cooledphotomultiplier on the 50-cm telescope at ESO on 37 nights during1982-1983 are reported. The data are presented in tables and graphs andbriefly characterized.
| Radial velocities of bright southern stars. I - 139 B-type HR and FK stars
Radial velocity determinations for 139 southern B stars in the BrightStar, FK4, and FK4 Supplement catalogues and for 53 bright southernlate-type stars are presented, based on coudespectrograms taken with theESO 1.5 m telescope at La Silla. The programs, observations,measurements, and reductions are described. Among the data presented arethe visual magnitude, spectral class, mean error, E/T variabilityparameter, velocity of interstellar lines, and rotation class.
| Four-colour UVBY and H-beta photometry of field stars - Double-lined spectroscopic binaries, G type dwarfs and early type FK4 stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977A&AS...29..313O&db_key=AST
| Bright southern stars of astrophysical interest
The paper lists a number of bright peculiar stars in the SouthernHemisphere discovered on 20-A/mm spectrograms. Recent information isalso given for a few known peculiar objects. The lists include: oneLambda Boo star, 4 Hg and other Bp stars, 7 Am stars, 17 shell oremission-line stars, and 37 double-lined spectroscopic binaries, amongwhich are two triple-lined, four composite, eight variable or eclipsing,and three peculiar shell and/or emission-line systems.
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