Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
|
Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
|
The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
|
Origin and Evolution of the Cepheus Bubble
We have imaged a 10 deg x 10 deg region of the Cepheus bubble in the J =1-0 line of CO and the 21 cm line of atomic hydrogen. The CO emissiondefines a giant expanding shell 120 pc in diameter, which is similar tothat seen in the IRAS sky maps. We estimate the total gas mass in theregion to be ~4 x 10^5 M_ȯ. The total kinetic energy from theobserved spread of velocities of the molecular clouds is ~10^51 ergs. Wesuggest that the members of earlier generations of massive stars in NGC7160 are responsible for the origin of the Cepheus bubble. These starscreated an expanding compressed shell of gas that became gravitationallyunstable at an age of ~7 Myr. The members of the Cepheus OB2 associationcomprise the second, intermediate generation of stars in this regionthat formed as a consequence of this instability. The numerous colorselected IRAS point sources represent the third and youngest generationof stars in this region. Our observations suggest the great importanceof sequentially triggered star formation in the region of the Cepheusbubble.
|
Spectroscopic investigation of bright stars in the CEP OB2 association.
Not Available
|
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.
|
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.
|
Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
|
Galactic OB associations in the northern Milky Way Galaxy. I - Longitudes 55 deg to 150 deg
The literature on all OB associations was reviewed, and their IRAS pointsource content was studied, between galactic longitude 55 and 150 deg.Only one third of the 24 associations listed by Ruprecht et al. (1981)have been the subject of individual studies designed to identify thebrightest stars. Distances to all of these were recomputed using themethod of cluster fitting of the B main sequence stars, which makes itpoossible to reexamine the absolute magnitude calibration of the Ostars, as well as for the red supergiant candidate stars. Also examinedwas the composite HR diagram for these associations. Associations withthe best defined main sequences, which also tend to contain very youngclusters, referred to here as OB clusters, have extremely few evolved Band A or red supergiants. Associations with poorly defined mainsequences and few OB clusters have many more evolved stars. They alsoshow an effect in the upper HR diagram referred to as a ledge byFitzpatrick and Garmany (1990) in similar data for the Large MagellanicCloud. It is suggested that the differences in the associations are notjust observational selection effects but represent real differences inage and formation history.
|
Extinction law survey based on UV ANS photometry
The paper presents an extensive survey of interstellar extinction curvesderived from the ANS photometric measurements of early type starsbelonging to our Galaxy. This survey is more extensive and deeper thanany other one, based on spectral data. The UV color excesses aredetermined with the aid of 'artificial standards', a new techniqueproposed by the authors which allows the special check of Sp/L match ofa target and the selected standard. The results indicate that extinctionlaw changes from place to place.
|
Groups of stars with common motion in the Galaxy. Groups of O and B stars
Not Available
|
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.
|
A survey of radio emission from Galactic OB stars
Radio continuum observations of 88 O-type and early B-type stars areexamined. Results are presented for a subset of these stars which formsa distance-limited sample of all OB stars within 2.5 kpc of the sun.Mass loss rates are derived for HD 15570, HD 166734, HD 151804, HD152408, Alpha Cam, HD 169454, and Zeta Sco. All of these very luminousOB stars are found to be losing mass at a rate on the order of 10 to the-5 solar masses/yr. Multifrequency observations confirm the free-freeinterpretation for Zeta Pup and provide evidence for variability in thefree-free sources P Cygni and Cyg OB2 No. 12.
|
Mass loss from stars : the universal formula for mass loss rate
Not Available
|
Hot components and circumstellar grains in M supergiant syncretic binaries
Ultraviolet and infrared spectra were obtained in order to study grainsin cool star and hot star syncretic type binaries. Grains are found inonly about half of the syncretic systems. The results suggest thatgrains have not formed in many syncretic systems because of ultravioletradiation from the hot star. Circumstellar extinction could not beunambiguously detected in those systems with grains.
|
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.
|
Mass loss rates in the Hertzsprung-Russell diagram
Mass loss rates have been collected for 271 stars of spectral type Othrough M, primarily of population I. Good agreement is found forresults obtained according to six different methods, and it is shownthat the mass loss rate data can be well represented by one empiricalinterpolation formula as a function of the effective temperature andluminosity. The chemically evolved stars are shown to have mass lossrates which are larger than those of normal stars occupying the samepositions in the Hertzprung-Russell diagram by factors of 160 forWolf-Rayet stars and 11 for C-type stars.
|
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.
|
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.
|
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.
|
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.
|
Spectrophotometric investigation of OB stars in the region of the association CEP OB2
The results are given of spectrophotometric investigation of 39 OB starsin the region of the association Cep OB2. The blue (4000-4800 A)absolute spectrophotometric gradients, the color excesses in the UBVsystem, and the distances of these stars have been determined. Analysisof the results suggests that the absorbing material is basicallyconcentrated within the association itself.
|
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.
|
A search for ring nebulae around Of stars
The Palomar Sky Survey prints have been used in a search for ringnebulae produced by the stellar wind, which involved the examination ofthe fields around 72 types of Of stars. It is found that for about halfof these stars, such ring nebulae as might exist would probably beunobservable because of the heavy absorption of bright H-alphabackground emission. Nevertheless, the H II regions surrounding 14 ofthe Of stars are found to exhibit ringlike structure.
|
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
|
Some characteristics of the young open cluster Trumpler 37.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976PASP...88..865G&db_key=AST
|
The abundance of negative hydrogen in small hot interstellar clouds
The observed intensities of the diffuse interstellar absorption band at4430 A have minimum values, for given stellar distances, that areequivalent to the reddening caused by the small Ambarzumian-type cloudsstudied by Stromgren (1972). This indicates that there is no negativehydrogen present between these clouds, which are then identified withthe hot H I phase of interstellar matter. The equilibrium density of H-inside such clouds is calculated from mean densities of neutral hydrogenatoms and free electrons, derived from radio observations for the localregion outside the large Orion-arm clouds. The filling factor of thesmall clouds is taken to be the same as that preserved in the structureof the Gum Nebula from before its ionization. An electron temperature of3375 K corresponding to the local degree of ionization of thesmall-cloud hydrogen then leads to a mean density of negative hydrogenequal to 20 trillions per sq cm per kpc, in agreement with the observeddiffuse-band intensities.
|
Wavelength dependence of interstellar polarization and ratio of total to selective extinction
A multichannel polarimeter-photometer which uses dichroic filters toseparate the (UBVR) spectral regions is described. The instrument wasused with a 24-inch rotatable tube telescope for polarimetricobservation of nearby stars. Polarization data for 364 nearby stars aretabulated, together with the wavelength dependence of linear andinterstellar polarization.
|
On the strength of H alpha in the O-stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974MNRAS.166..463O&db_key=AST
|
On the kinematical and spatial coincidence of optical and radio spiral arms in our galaxy.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&A....24..393M&db_key=AST
|
