Large-Scale Structure and Dynamics of Cassiopeia OB7
A large region (9°×9°) surrounding the OB associationCassiopeia OB7 has been studied for signs of interaction between thestars and the ambient gas. A large half-shell has been detected in H Iaround Cas OB7, as well as in the infrared and partially in CO. Thishalf-shell covers a range of 20 km s-1 but could reach 40 kms-1 when extrapolating to the whole shell. The structure is120 pc across if located at 2 kpc, the distance to Cas OB7. At thisdistance, we estimate the mass of the shell to be approximately 30,000Msolar. Interestingly, all Cas OB7 members are located wellwithin the edge of this shell. We believe that there is a strong hint ofinteraction between the gas and the stars based on morphologicalevidence. The velocity of both objects (association and shell) and theirrespective distance are also in agreement. We explain the missing halfby an expansion into the interarm region.
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UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
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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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Groups of stars with common motion in the Galaxy. Groups of O and B stars
Not Available
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Correlation between the very broad structure and the continuum in FUV extinction curves
There exists a correlation between the amount of the far UV extinctionand the relative strength of the very broad structure in the 500 to 600nm wavelength region of the interstellar extinction curves. For a givencolor excess E(B-V) values of the UV extinction large than averagecorrespond to larger strengths of the very broad structure (VBS) andvice versa. The VBS seems to be a common dust-related feature.
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Groups of stars with common motion in the Galaxy - Groups of B stars of luminosity classes I and II and their comparison with groups of long-period Cepheids and open clusters
In a sample of 93 stars of luminosity classes I and II, ten groups withcommon motion in space are isolated. The reality of five groups isestablished by numerical experiment. A comparison is made with groups oflong-period Cepheids and open clusters. Regularities in the distributionof groups of different objects in space are found. The reality of therotation of a star aggregate consisting of three Cepheid groups isestablished.
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H-alpha as a tracer of mass loss from OB stars
This paper investigates the use of the H-alpha emission from stellarwinds of OB stars to determine the stellar mass-loss rate. The power inH-alpha emitted by the wind can be parameterized in terms of thetemperature and the density field of the wind. A simple expression isderived which relates the observed H-alpha luminosity to the stellarmass-loss rate, the stellar radius, the velocity law, and the stellareffective temperature. This expression is calibrated for the influenceof the velocity law using a sample of Galactic OB stars with UVmass-loss rates. Consequently, the results depend on the validity of theUV rates. The derived velocity law for O stars turns out to be inagreement with the radiation-pressure-driven wind theory. There isevidence for a dependence of the velocity-law gradient on spectral type.The results for B stars, however, are more uncertain due to thedependence on the adopted mass accretion rate/L relation. Application ofthe calibrated H-alpha luminosity/mass-loss rate relation to a sample of149 galactic OB stars shows that mass accretion rate can be reliablydetermined from H-alpha. Due to the moderate amount of observing timerequired to derive mass accretion rate from H-alpha, this method may beapplied successfully to investigate mass-loss effects in extra-Galacticstars.
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The interstellar 217 NM band - A third catalogue of equivalent widths
A catalog of equivalent widths of the 217 nm interstellar absorptionband as well as other parameters characterizing the extinction curve inthe ultraviolet has been compiled for 790 O and B stars. A relativelytight correlation between the equivalent width of the 217 nm band andE(B-V) indicates that the absorber of this band is connected with thepopulation of larger interstellar grains responsible for the visualextinction. The parameter characterizing the amount of extinction in thefar UV is only weakly correlated with E(B-V), a result in accord withthe assumption that a second population of very small grains causes therapid increase of the far-UV extinction.
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Observations of interstellar diffuse absorption band at 4430 A
Observations of the interstellar diffuse absorption band at 4430 A for800 O and B stars in Neckel's (1967) catalog are being carried out, and482 spectra obtained up to September 1983 have been reduced. It isconfirmed that the strength of the interstellar diffuse absorption bandat 4430 A does not simply relate to the abundance of interstellar grainson the line of sight. The relation between the color excess E(B-V) andthe equivalent width of the band to the direction of l = 130-140 deg andb = -5 to +5 deg shows that some parameter(s) other than E(B-V) is (are)needed to understand the cause of this band.
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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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A catalog of ultraviolet interstellar extinction excesses for 1415 stars
Ultraviolet interstellar extinction excesses are presented for 1415stars with spectral types B7 and earlier. The excesses with respect to Vare derived from Astronomical Netherlands Satellite (ANS) 5-channel UVphotometry at central wavelengths of approximately 1550, 1800, 2500, and3300 A. A measure of the excess extinction in the 2200-A extinction bumpis also given. The data are valuable for investigating the systematicsof peculiar interstellar extinction and for studying the character of UVinterstellar extinction in the general direction of stars for which theextinction-curve shape is unknown.
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The binary system MWC 349
The ionized zone surrounding MWC 349 has been resolved using the VLA. Onthe basis of a radio continuum map, it is concluded that there is aphysical interaction between the two stellar components of MWC 349, andthat the system is therefore a binary. The B component can be classifiedas a B0 III star, yielding a distance of about 1.2 kpc for the binary.The low ratio of infrared to short-wavelength luminosity in the Acomponent suggests a circumstellar dusty region of special geometry. Itis proposed that an appreciable dust and gas disk surrounds the star,modifying the symmetry of its H II region, and yielding the low infraredluminosity and perhaps its extra circumstellar extinction.
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Mass loss rates for northern OB-stars
A mass loss survey of 44 O- and early B-type stars in northern OBassociations is presented. For 22 stars mass loss rates were derivedfrom H-alpha equivalent widths using the method of Klein and Castor(1978). For 15 stars upper limits of the mass loss rates were estimated.For the remaining 7 stars H-alpha and H-beta equivalent width values aregiven but no quantitative evaluation of M-dot was possible. The resultsare compared with present ideas concerning the relation between massloss and other basic stellar parameters.
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Meridian observations made with the Carlsberg Automatic Meridian Circle at Brorfelde (Copenhagen University Observatory) 1981-1982
The 7-inch transit circle instrument with which the present position andmagnitude catalog for 1577 stars with visual magnitudes greater than11.0 was obtained had been equipped with a photoelectric moving slitmicrometer and a minicomputer to control the entire observationalprocess. Positions are reduced relative to the FK4 system for each nightover the whole meridian rather than the usual narrow zones. Thepositions of the FK4 stars used in the least squares solution are alsogiven in the catalog.
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A study of B-type supergiants with the uvby,beta photometric system
The applicability of the uvby,beta photometric system to theclassification and study of B-type supergiants (BTS) is investigatedusing published data on 157 BTS and observations of 17 BTS made with the36-in. reflector at McDonald Observatory. The results are presented intabular form and analyzed to produce preliminary calibrations ofluminosity class vs. beta index and of absolute magnitude (Mv) vs. beta(or delta Mv vs. delta beta) for four associations of stars. Theeffectiveness of various color indices as temperature indicators isdiscussed. It is shown that there is good correspondence between MK anduvby,beta classifications of B-type main-sequence stars, giants, andBTS, confirming the usefulness of the uvby,beta system in furtherresearch on BTS.
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A survey of interstellar neutral potassium. I - Abundances and physical conditions in clouds toward 188 early-type stars
Observations of interstellar absorption in the resonance doublet 7664,7698 A of neutral potassium toward 188 early-type stars at a spectralresolution of 8 km/s are reported. The 7664 A line is successfullyseparated from nearly coincident telluric O2 absorption for all but afew of the 165 stars for which K I absorption is detected, makingpossible an abundance analysis by the doublet ratio method. Therelationships between the potassium abundances and other atomicabundances, the abundance of molecular hydrogen, and interstellarreddening are investigated.
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Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978ApJS...38..309H&db_key=AST
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Noncircular motions in the Perseus spiral arm
An examination of the motions of the optical spiral tracers in thePerseus arm reveals a clear kinematic separation between the inner andouter sides of the arm. Those objects on the inner or near side have amean velocity residual of -10.7 km/s, while those on the outer or farside have a mean positive residual of +7.0 km/s. These velocityresiduals are interpreted in terms of the linear density-wave theory asstreaming motions between the sides of the arm. Plausible solutions forthe amplitudes of the noncircular motions yielded 10 to 20 km/s and 7 to15 km/s for the radial and tangential components, respectively. Theseresults are about twice the amplitudes suggested by the theory.
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A Comparison of the Luminosities of Perseus-Arm Stars in the Hγ and MK Systems
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJ...171..285C&db_key=AST
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Some Spectroscopic Characteristics of the OB Stars: an Investigation of the Space Distribution of Certain OB Stars and the Reference Frame of the Classification
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJS...23..257W&db_key=AST
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The space distribution and kinematics of supergiants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970AJ.....75..602H&db_key=AST
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Optical and Radio Evidence of Large-Scale Peculiar Motions in the Cassiopeiaperseus Arm
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1968ApJ...152.1019R&db_key=AST
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Catalogue d'etoiles O et B.
Not Available
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Photoelectric 4430 A observations of 506 O, B and A stars.
Not Available
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Troisième catalogue de l'Observatoire de Besançon comprenant 764 étoiles réduites à 1950, 0 sans mouvement propre et 326 étoiles FK3 pour l'époque moyenne d'observation
Not Available
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Comparison of radial velocities of the OB-stars and Cepheids in the Perseus arm
Not Available
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Interstellar Absorption Lines in Distant Stars. I. Northern Milky way.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1957ApJ...125...42M&db_key=AST
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Line Broadening in the Spectra of o- and Early B-Type Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1956ApJ...124..173S&db_key=AST
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Studies in Galactic STRUCTURE.II.LUMINOSITY Classification for 1270 Blue Giant Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJS....2...41M&db_key=AST
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Carbon Stars at the Galactic Equator in a Zone 4° Wide.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1954ApJ...120..129N&db_key=AST
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INHABITED SKY
