Rings around Lyra.
Not Available
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Photometric and Spectroscopic Study of Stars in the Field of the Young Open Cluster Roslund 4
We present photometric and spectroscopic observations performed in thefield of the Galactic open cluster Roslund 4, which contains the twocataloged nebulae IC 4954 and IC 4955. UBVRI photometry was carried outin a field of 11'×6' around the clustercenter. Medium-resolution optical spectroscopy has been obtained for 41stars, including previously selected main-sequence and pre-main-sequencecandidate cluster members. Narrowband Hα, [S II], and continuumimages have been secured. The observations allow us the measurement ofdifferent physical parameters for the cluster. Assuming an absorptioncoefficient AV/E(B-V)=3.1 and a reddening slopeE(U-B)/E(B-V)=0.72, we obtain a color excess E(B-V)=1.1+/-0.2 and adistance modulus DM0=11.7+/-0.5. Fitting of isochrones to thecolor-magnitude diagrams gives logage(yr)=7.2+/-0.2, and thespectroscopic measurements provide the value VR=-15.7+/-5.2km s-1 for the heliocentric radial velocity. Among the 41stars with spectroscopic data, 11 stars are probable cluster members onthe basis of their radial velocity, and another 10 are considered aspossible members. Two probable member stars of spectral types A5 and G1show hints of absorption in the Li I 6708 Å line, with respectiveequivalent widths of 0.10 and 0.28 Å, and 22 stars of spectraltypes from B2 to G0 show different degrees of emission in Hα, [NII], and [S II] lines. With the exception of three stars of spectraltype earlier than A0, the emission of which is mainly photospheric, allother emissions seen in Hα and forbidden lines have a nebularorigin. They arise in an ionized cloud that surrounds the cluster and iscausing diffuse emission and, possibly, local variations in theextinction law from star to star. In addition to the stars, spectra ofseveral nebular condensations with relatively higher excitation havebeen analyzed. Two of them have been suggested to be Herbig-Haro (HH)objects. Our spectra indicate that only one of these condensations couldbe considered as an HH object.
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Fundamental parameters and new variables of the galactic open cluster NGC 7128
CCD photometry in Johnson UBV and Strömgren uvby systems andmedium-resolution spectroscopy of the galactic open cluster NGC 7128 arepresented. Spectral types of the brightest 12 stars in the cluster fieldwere determined based on equivalent widths of the Hα and the Hei6678-Å line. The spectroscopic observations also revealed twoobvious and one probable Be-type stars showing Hα emission. Theanalysis of the photometric diagrams gave a colour excess ofE(B-V)=1.03+/-0.06mag, a distance modulus DM=13.0+/-0.2mag and an ageabove 10Myr. Time-resolved photometric observations obtained on onenight resulted in the detection of short time-scale light variations ofseven new and three already known variable stars in the cluster field.
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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.
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A preliminary compilation of DS-programme star positions
A catalog is presented of the double-star-program (DS-program) starpositions, listing right ascensions for 930 DSs and declinations for1225 DSs of the program. The positions were compiled from the observedvalues obtained between 1980 and 1987 with the meridian circles of sixUSSR observatories (the Moscow, Kazan', Kiev, Khar'kov, Odessa, andTashkent Observatories) and the Belgrade Observatory. The measurementsand the treatment of the observational material were performed using therelative method, and the FK-4 system stars were used as reference stars.
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Empirical temperature calibrations for early-type stars
Three temperature calibrations of suitable photometric quantities havebeen derived for O and B stars. A sample of 120 stars with reliableT(eff.) determinations has been used for establishing each calibration.The different calibrations have been critically discussed and compared.Temperature determinations for 1009 program stars have been obtainedwith an accuracy of the order of 10 percent.
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A list of MK standard stars
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Catalog of O-B stars observed with Tokyo Meridian Circle
A catalog of the O-B stars, selected from 'Blaauw-Parenago' list andRubin's catalog, has been compiled on the FK4 system by the observationsmade with Gautier 8-inch Meridian Circle at the Tokyo AstronomicalObservatory during the period, 1971 to 1979. It contains 1059 stars andwas compiled for the future establishment of high precision propermotions of O-B stars.
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The interstellar 2200 A band - A catalogue of equivalent widths
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Visual multiples. VII - MK classifications
Classifications are given for 865 components of visual multiples; theyshow no systematic differences from the MK system, and the random errorsare one subclass in type and two-thirds of a luminosity class. It isfound that at least 1% of the F-type IV and V stars are weak-lined, 32%of the A4-F1 IV and V stars are Am, and 5% of the A0-A3 IV and V starsare early-type Am. Attention is called to the large fraction (55%) ofthe A3-A9 III-V stars that are of luminosity classes III or IV, unlikethe percentage (16%) at neighboring types.
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Spectral classification from the ultraviolet line features of S2/68 spectra. V - Supplement series
The paper presents the ultraviolet classification of more than 450 B-Aand F spectra obtained with the sky survey telescope mounted on the TD1satellite. Concerning abnormal objects, attention is given to the Bestars, the binary stars, the helium weak stars, and the lambda Booobjects. With regard to Be stars, it is concluded that the 1930 Awavelength feature is linked to the existence of either shell structuresor Fe II emission lines in the visual spectral range. In addition, it issuggested that stellar spectra at wavelengths of 1410, 1610-20 and 2400A are equivalent to the He-weak group in the classical range.
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H-beta photometry of northern intermediate galactic latitude early-type stars and galactic structure away from the plane
Photoelectric H-beta photometry is presented for 255 early-type stars atintermediate galactic latitudes. Absolute magnitudes and distances arederived for the more luminous stars. Those with visual magnitudes lessthan or equal to 2.5 and at distances of up to 1 kpc from the galacticplane may follow the spiral structure in the plane.
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UBV photometry and MK spectral classification of northern early-type stars at intermediate galactic latitudes
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977MNRAS.180..691H&db_key=AST
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Positions moyennes et mouvements propres de 355 etoiles DU GC de la zone de declinaison +33 +36.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976A&AS...26..219M&db_key=AST
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Spectral Classifications of 239 Early-Type Stars
Not Available
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Photoelectric distances of 461 Northern OB-stars and galactic structure from Hγ- luminosities Author: Beer, A.
Abstract image available at:http://adsabs.harvard.edu/abs/1964MNRAS.128..261B
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Photoelectric measures of the 4430 A diffuse interstellar band
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1963MNRAS.125..141W&db_key=AST
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Recherches sur les Proprietes des Etoiles Doubles ou Multiples Largement Separees EN Relation avec les Problemes d'Evolution
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Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1953ApJ...117..313J&db_key=AST
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A search for stars of the BET CMa type.
Not Available
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