The Carina Spiral Feature: Strömgren-Hβ photometry approach. I. The photometric data-base
A data-base collating all uvbybeta photometry available at present forO-B9 stars brighter than 10th visual magnitude in the field of theCarina Spiral Feature is presented. The completeness and homogeneity ofthe data-base are discussed.Based on CDS data.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/410/523
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New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
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Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
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Five-colour photometry of OB-stars in the Southern Hemisphere
Observations of OB-stars, made in 1959 and 1960 at the Leiden SouthernStation near Hartebeespoortdam, South Africa, with the VBLUW photometerattached to the 90 cm light-collector, are given in this paper. They arecompared with photometry obtained by \cite[Graham (1968),]{gra68}\cite[Walraven & Walraven (1977),]{wal77} \cite[Lub & Pel(1977)]{lub77} and \cite[Van Genderen et al. (1984).]{gen84} Formulaefor the transformation of the present observations to those of\cite[Walraven & Walraven (1977)]{wal77} and \cite[Lub & Pel(1977)]{lub77} are given. Table 4 is only available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/Abstract.html
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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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Stromgren and Hβ photometry of OB stars in the region of the Carina Spiral Feature
Stromgren and Hβ photometry of 130 stars in the Carina section ofthe Milky Way is presented. The color excesses and the distances of allstars are obtained. A good agreement is found between the CM and HRdiagrams and the spatial distribution of these stars. Tables 1, 2, 4 and5 are only available in electronic form at the CDS via anonymous ftp to130.79.128.5 or via http://cdsweb.u-strasbg.fr/Abstract.html
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A Radial Velocity Database for Stephenson-Sanduleak Southern Luminous Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....113..823R&db_key=AST
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Long-term spectroscopic monitoring of BA-type supergiants. III. Variability of photospheric lines.
We obtained time series of spectra with high S/N and high resolution inwavelength and time of early-type A and late-type B supergiants (cf.Kaufer et al. 1996A&A...305..887K, Paper I, and Kaufer et al.1996A&A...314..599K, Paper II for the analysis of the variability ofthe stellar envelopes). In this work we inspect the time variations ofthe numerous photospheric line profiles in the optical spectrum. We findcomplex cyclical variations of the radial velocities with a typicalvelocity dispersion of σ=~3km/s. The correspondingequivalent-width variations are less than 1% of their mean if we assumea common modulation mechanism for both radial velocities and equivalentwidth. We do not find any depth dependence of the velocity fields in themetallic lines. For αCyg the Balmer lines show an increase of theradial velocity from H27 to H8 by 3km/s, which is identified with theonset of the radially accelerating velocity field of the stellar wind.The Cleaned periodograms of the radial-velocity curves show thesimultaneous excitation of multiple pulsation modes with periods longerand shorter than the estimated radial fundamental periods of theobjects, which might indicate the excitation of non-radial and radialovertones, respectively. The analysis of the line-profile variations(LPV) of the photospheric line spectrum reveals prograde travellingfeatures in the dynamical spectra. The travelling times of thesefeatures are in contradiction to the possible rotation periods of theseextended, slowly rotating objects. Therefore, we suggest that thesefeatures should be identified with non-radial pulsation modes, possiblyg-modes, of low order (l=|m|<~5).
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The ROSAT all-sky survey catalogue of optically bright OB-type stars.
For the detailed statistical analysis of the X-ray emission of hot starswe selected all stars of spectral type O and B listed in the Yale BrightStar Catalogue and searched for them in the ROSAT All-Sky Survey. Inthis paper we describe the selection and preparation of the data andpresent a compilation of the derived X-ray data for a complete sample ofbright OB stars.
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Long-term spectroscopic monitoring of BA-type supergiants. II. High-velocity absorptions in βOri and HD96919.
During our extended monitoring campaigns on late B and early A-typesupergiants (Kaufer et al. 1996A&A...305..887K, Paper I) we haveobserved extraordinarily deep and highly blue-shifted absorption eventsin the Hα line. In this work, new time-series observations showingthe most extreme cases of such events observed so far are presented fortwo objects, βOri (B8Ia) and HD96919 (B9Ia). The development ofthese high-velocity absorption (HVA) events in velocity and time arediscussed: the HVAs show no signs of spherically symmetric mass-lossevents with subsequent accelerated propagation into the wind. Theabsence of unshifted line emission in connection with the HVAs isespecially indicative of the non-sphericity of the active circumstellarregions. Simultaneously with the blue-shifted absorption, red-shiftedabsorption is found in Balmer and metallic lines, primarily during theonset of the developing event, which clearly reveals the complexstructure of the involved velocity fields. Mass outflow and mass infallare present in the envelope. As a picture for the circumstellarstructures that cause the sudden appearance of the HVAs over a largevelocity range, localized regions of enhanced mass loss on the stellarsurface, which build up extended, rotating streak lines in theequatorial plane are suggested. Finally, the role of a criticalionization structure in the condensed structures is discussed.
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Long-term spectroscopic monitoring of BA-type supergiants. I. Halpha_ line-profile variability.
We have obtained time series of spectra in the wavelength range4000-6800 A over several months with high S/N and high resolution inwavelength (λ/{DELTA}λ=~20000) and time ({DELTA}t=~1d) ofthe late-type B and early-type A supergiants HD91619 (B7Ia), βOri(B8Ia), HD96919 (B9Ia), HD92207 (A0Ia), HD100262 (A2Ia) and αCyg(A2Ia). Halpha_ is found to show broad emission extended toabout +/-1200km/s for all objects except αCyg. Due to the lack ofstrong line-emission in Halpha_ the electron-scatteredphotons are expected to originate in deep atmospheric layers. In all ofthe objects the Halpha_-line profiles are found to be highlyvariable on different time scales reaching from days to months. Patternsof variation in Halpha_ are found to be quite symmetric aboutthe systemic velocity and are mainly due to variable blue andred-shifted emission superimposed on almost constant photospheric and/orwind profiles. These V/R variations are interpreted in terms of axialsymmetry of the envelopes of these objects. Time-series analyses of thevariations reveal Halpha_ time scales up to a factor of 6longer than expected radial fundamental pulsation periods but consistentwith rotational periods. Therefore, rotational modulation as a possiblesource of variability is concluded. Corotating weak magnetic surfacestructures are suggested as the source for a rotationally modulatedlower wind region. Suddenly appearing deep and highly blue-shiftedabsorptions in Halpha_ are ascribed to instabilities of theionization structure of the wind. Outwards propagating discreteabsorption components have been observed only once in HD92207.
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A spectroscopic database for Stephenson-Sanduleak Southern Luminous Stars
A database of published spectral classifications for objects in theStepenson-Sanduleak Luminous Stars in the Southern Milky Way catalog hasbeen compiled from the literature. A total of 6182 classifications for2562 stars from 139 sources are incorporated.
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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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An atlas of ultraviolet P Cygni profiles
We have selected spectra of 232 stars from the International UltravioletExplorer (IUE) archives for inclusion in an atlas intended for varioususes but tailored especially for the study of stellar winds. The atlascovers the range in spectral types from O3 to F8. The full atlas coversthe reduced and normalized high resolution spectra from the IUE long-and short-wavelength spectrographs. Here we discuss the selection of thestars and the data reduction, and we present in velocity units theprofiles of lines formed in the stellar winds. The selected lines covera wide range of ionizations, allowing a comparison of the profiles fromdifferent ions in the wind of each star and a comparison of thedifferent wind lines as a function spectral type and luminosity. We alsopresent the basic data on the program stars to facilitate study of thedependence of wind features on stellar parameters such as luminosity,temperature, escape velocity, and v sin i. We provide an overview of thecharacteristic behavior of the wind lines in the H-R diagram. Thecomplete spectra are available in digital form through the NASAAstrophysics Data System (ADS). We offer a description of the electronicdatabase that is available through the ADS and guidelines for obtainingaccess to that database.
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Spectroscopic monitoring of BA-type supergiants.
Not Available
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Distribution of hot stars and interstellar dust in Carina.
Not Available
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Bright blue stars in VELA observed with the 'Glazar' space telescope
Seventy-one stars brighter than about 9 m have been detected at 1640 Ain the Vela region with the space telescope Glazar. It is shown thatmost of the detected stars belong to a B-type stellar association at adistance of 460 pc and to two OB stellar associations at distances of1100 pc and 1700 pc. The existence of B-type stellar association at adistance of 110 pc is suspected. A new O-type star cluster, which is apossible nucleus of the OB stellar association at 1700 pc, has beendetected. The distribution of the absorbing matter in the observed areais studied. We presume that the stars HD 75 063 and 76 534 are probablyembedded in a circumstellar dust shell. All observed stars, includingthose with unknown spectra, are early type stars.
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An Einstein Observatory SAO-based catalog of B-type stars
About 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars.
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Observations of a region of the Carina OB 1 association using the "Glazar" space telescope.
Not Available
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The calibration of the Stromgren photometric system for A, F and early G supergiants. I - The observational data
An empirical calibration of the Stromgren uvby-beta photometric systemfor the A, F, and early G supergiants is being derived. This paperexplains the observational program and the photometric reductiontechniques used and presents a catalog of new Stromgren photometry forover 600 A, F, and G supergiants.
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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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The maximum amplitude of the optical micro-variations of massive O-F type stars (or Alpha Cygni variables, including LBV's or S DOR variables) across the HR diagram
The maximum light amplitude (MLA) of the microvariations of nearly 100massive stars with spectral type O 3-F8 are collected from theliterature and unpublished material. These variables, called the AlphaCygni variables, also include the LBVs or S Dor type variables. The SDor type variables must be in a quiescent stage to detect theirintrinsic variations properly. The log T(eff)/MLA diagram exhibits aclear separation between S Dor type variables and the normal Alpha Cygnivariables (the majority). The results suggest that the outer layers ofboth types of stars where gravity waves presumably occur, differphysically from each other.
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Non-canonical insights into the evolution of stars. II - Are variable supergiants indeed pulsating?
It is shown that the interpretation of the observed semiperiodicluminosity or radial-velocity variations of supergiants in terms ofnonradial pulsations is not as straightforward as often believed. Theobserved semiperiodic luminosity-light dependence can also be derivedunder the assumption of rotational modulation or orbital motion in abinary system. Consideration is also given to the hypothesis that atleast some of the variable supergiants are actually contacts ornear-contacts of the more massive components of unrecognized binarysystems with a low mass-ratio.
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Small Magellanic Cloud: H-gamma-line equivalent widths and luminosity classes of the brightest blue star members
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1987A&AS...69..421A&db_key=AST
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High-resolution spectroscopy of the unique eclipsing binary system - Epsilon Aurigae
H-alpha and Na D line profiles of the Epsilon Aur system acquired duringthe eclipse of 1982-84 are presented. As in previous eclipses, theH-alpha absorption core shows striking, systematic changes in width andradial velocity. H-alpha also exhibits time-varying blueshifted andredshifted emission in the line wings. It is suggested that the H-alphaemission-wing variability is due solely to ongoing processes in theextended atmosphere of the supergiant primary. As the eclipseprogresses, the Na D absorption lines deepen and widen, then decrease insize as their weak emission components strengthen. The time-developmentof the Na D line profiles over the duration of the eclipse is consistentwith the eclipsing object being a massive, cool, rotating, gaseous disk.The observed Na D line velocities combined with derived values for themass and spatial extent of the secondary suggest that the disk is losingmaterial.
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Low dispersion spectrophotometry of bright early-type stars
Intensity distributions for 79 stars of spectral types O9 to A3, plus anF3 star and 7 standard stars, are presented. The observations cover awavelength range from 3300 to 6000 A. The internal errors are discussed.Synthetic uby colors are obtained for all the stars observed, and arecompared with observed published data.
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Erratum - Distant Blue Stars in the Southern Milky-Way
Not Available
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New UBVRI photometry for 900 supergiants
A description is presented of the results obtained in connection with asystematic program of supergiant photometry on the Johnson UBVRI system.During the eight years after the start of the program, almost 1000 starshave been observed, about 400 three or more times each. The originalselection of stars used the spectral type catalog of Jaschek et al.(1964) to choose supergiants. Since observations were possible from bothChile and Canada, no declination limits were imposed, and no particularselection criteria were imposed other than to eliminate carbon stars.These are so red as to require enormous extrapolations of thetransformation equations.
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UBV photometry for southern OB stars
New UBV photometry of 1227 OB stars in the southern Milky Way ispresented. For 1113 of these stars, MK spectral types have been reportedpreviously in a comprehensive survey to B = 10.0 mag.
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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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