Contents
Images
Upload your image
DSS Images Other Images
Related articles
A catalogue of eclipsing variables
A new catalogue of 6330 eclipsing variable stars is presented. Thecatalogue was developed from the General Catalogue of Variable Stars(GCVS) and its textual remarks by including recently publishedinformation about classification of 843 systems and making correspondingcorrections of GCVS data. The catalogue1 represents thelargest list of eclipsing binaries classified from observations.
| Photometry of 20 eclipsing and ellipsoidal binary systems
ERRATUM: In the published paper the phase diagrams of pi Sco and AL Sclwere ommitted. The version reproduced in JAD11, 7 is the completeversion. A total of almost 2000 V observations of 20 eclipsing andellipsoidal bright binary stars was collected between 1991 and 2001 forthe purpose of determining more recent epoch ephemerides for the lightcurves than are available in the literature. The original purpose was toprovide the Sydney University Stellar Interferometer (SUSI) with orbitalperiods and particularly the accurate times of minimum separation (lightcurve minima), so that the SUSI observations need not be used todetermine them.This paper provides the periods, the times of primary minima and thephases of secondary minima for the 20 stars at an epoch as near aspossible to the year 2000. No attempt has been made in this report todetermine other parameters such as {apsidal motion} or stellar radii.Since the program was started in 1991, data for these stars taken in theperiod from late 1989 to early 1993 has also been available from theHipparcos satellite; the light curves shown here include both sets ofobservations.
| A Medium Resolution Near-Infrared Spectral Atlas of O and Early-B Stars
We present intermediate-resolution (R~8000-12,000) high signal-to-noise(S/N) H- and K-band spectroscopy of a sample of 37 optically visiblestars, ranging in spectral type from O3 to B3 and representing mostluminosity classes. Spectra of this quality can be used to constrain thetemperature, luminosity, and general wind properties of OB stars, whenused in conjunction with sophisticated atmospheric model codes. Mostimportant is the need for moderately high resolutions (R>=5000) andvery high signal-to-noise (S/N>=150) spectra for a meaningful profileanalysis. When using near-infrared spectra for a classification system,moderately high signal-to-noise (S/N~100) is still required, though theresolution can be relaxed to just a thousand or two. In the Appendix weprovide a set of very high-quality near-infrared spectra of Brackettlines in six early-A dwarfs. These can be used to aid in the modelingand removal of such lines when early-A dwarfs are used for telluricspectroscopic standards.
| Photometry of 20 eclipsing and ellipsoidal binary systems
A total of almost 2000 V observations of 20 eclipsing and ellipsoidalbright binary stars was collected between 1991 and 2001 for the purposeof determining more recent epoch ephemerides for the light curves thanare available in the literature. The original purpose was to provide theSydney University Stellar Interferometer (SUSI) with orbital periods andparticularly the accurate times of minimum separation (light curveminima), so that the SUSI observations need not be used to determinethem.This paper provides the periods, the times of primary minima and thephases of secondary minima for the 20 stars at an epoch as near aspossible to the year 2000. No attempt has been made in this report todetermine other parameters such as {apsidal motion} or stellar radii.Since the program was started in 1991, data for these stars taken in theperiod from late 1989 to early 1993 has also been available from theHipparcos satellite; the light curves shown here include both sets ofobservations.
| Catalogue of Algol type binary stars
A catalogue of (411) Algol-type (semi-detached) binary stars ispresented in the form of five separate tables of information. Thecatalogue has developed from an earlier version by including more recentinformation and an improved layout. A sixth table lists (1872) candidateAlgols, about which fewer details are known at present. Some issuesrelating to the classification and interpretation of Algol-like binariesare also discussed.Catalogue 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/417/263
| The Remarkable Alternating Spectra of the Of?p Star HD 191612
The spectrum of HD 191612 has been found to display large, recurrentvariations between two highly reproducible, peculiar states; at leastfour transformations have occurred since 1950. In one state, thespectral type is O6-O7, with C III λ4650 emission comparable to NIII λ4640 (the definition of the Of?p category) and P Cygniprofiles at He II λ4686 and Hα. In the other state, thespectral type is O8, with the C III emission absent, very strong N IIIλ4097 absorption, broad He II λ4686 absorption with narrowcentral emission (a profile that may be unprecedented in this line amongknown O-type spectra), and a broad asymmetrical absorption at Hα.One observing sequence over several consecutive nights shows no spectralvariations, practically ruling out a short-period, interacting binary asthe origin of the phenomenon; moreover, no significant radial velocityvariations have been found. Although the sporadic observational recordprior to the discovery of the variations in early 2001 precludesdefinite conclusions, it is possible that a given state is maintainedfor a decade or longer, but one transformation occurred within 13months, and the data obtained during 2002 suggest an event with ashorter timescale.The Of?p category currently contains only five members: three in theGalaxy and two in the Small Magellanic Cloud. The other two Galacticmembers also display bizarre and unexplained phenomena; in the case ofHD 108, they are strikingly similar to those described here. Because oftheir relatively high X-ray luminosities, all three Galactic objectshave been suggested to have collapsed companions. If the spectralvariations of HD 108 and HD 191612 are due to binary interactions, theyare likely multiyear, eccentric systems like WR 140 and η Carinae.The axisymmetric shell ejections of HD 148937 could have a similarorigin. Alternatively, these stars may be rapid rotators or in anunstable evolutionary transitional stage. Further intensivespectroscopic monitoring is required to reveal their nature.
| Rotational mixing in early-type main-sequence stars
We present quantitative observational investigations into the importanceof rotationally induced mixing in late-O stars. First, we conductnon-LTE, hydrostatic, plane-parallel H/He model-atmosphere analyses ofthe optical spectra of three of the most rapidly rotating late-Onear-main-sequence stars known: HD 93521 (O9.5 V), HD 149757 (ζOphiuchi; O9.5 V), and HD 191423 (ON9 III: n), all of which haveequatorial rotation velocities of ~430kms-1 and[formmu8]ωe/ωe(crit)~=0.9. Theanalysis allows for the expected (von Zeipel) variation ofTeff and logg with latitude. These three stars are found toshare very similar characteristics, including substantially enhancedsurface-helium abundances [formmu9](y~=0.2). Secondly, we compare thedistribution of projected rotational velocities for ON andmorphologically normal dwarf O stars, and demonstrate that the ON starsare drawn from a population with more rapid rotation. The resultsprovide qualitative support for rotationally induced mixing, althoughthere remain discrepancies between atmospheric and evolutionary models(which we show employ inappropriate mass-loss rates for late-Omain-sequence stars). We show that the most rapid rotator known, HD191423, is an ON star, and note the implied disparity between O/ONmorphology and surface helium abundance; we discuss consequences for theinterpretation of spectral morphology in O-type main-sequence stars. Wedemonstrate a new, purely spectroscopic, method of distancedetermination for rapid rotators, and thereby confirm that HD 93521 liesat ~2kpc, and is not, as previously suggested, a low-mass Population IIstar. Finally, our models contradict earlier claims of stronglydifferential surface rotation, and are consistent with uniform angularvelocity at the surface.
| The Orbit and Spectral Line Variations of the Massive Binary HD 163181 (V453 Scorpii)
We present revised orbital elements for the massive interacting binaryHD 163181, and we offer the first evidence of apsidal motion in theorbit (apsidal period U=510+/-100 yr). We searched for but found noobvious evidence of the secondary's spectral lines in our opticalspectra. We do observe, however, systematic profile variations withorbital phase that probably result from a gas stream from the Rochelobe-filling supergiant to the faint secondary. The relatively smallprojected rotational velocity of the primary (Vsini=88+/-3 kms-1), the faintness of the secondary, the reported lack oforbital motion in the Hα emission, and the presence of an IRexcess all suggest that the system is surrounded by an extensivecircumbinary disk (as is found in a similar binary, RY Scuti).
| Mass loss rate determination of southern OB stars
A sample of OB stars (eleven Of, one O and one B supergiant) has beensurveyed with the Australia Telescope Compact Array at 4.8 and 8.64 GHzwith a resolution of ~ 2 arcsec-4 arcsec. Five stars were detected;three of them have negative spectral indices, consistent withnon-thermal emission, and two have positive indices. The thermalradiation from HD 150135 and HD 163181 can be explained as coming froman optically thick ionized stellar wind. The non-thermal radiation fromCD-47deg 4551, HD 124314 and HD 150136 possibly comes fromstrong shocks in the wind itself and/or in the wind colliding region ifthe stars have a massive early-type companion. The percentage ofnon-thermal emitters among detected O stars has increased up to ~ 50%.The Of star HD 124314 clearly shows flux density variations. Mass lossrates (or upper limits) were derived for all the observed stars and theresults compared with non-radio measurements and theoreticalpredictions.
| 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
| Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
| ICCD Speckle Observations of Binary Stars. XXIII. Measurements during 1982-1997 from Six Telescopes, with 14 New Orbits
We present 2017 observations of 1286 binary stars, observed by means ofspeckle interferometry using six telescopes over a 15 year period from1982 April to 1997 June. These measurements constitute the 23dinstallment in CHARA's speckle program at 2 to 4 m class telescopes andinclude the second major collection of measurements from the MountWilson 100 inch (2.5 m) Hooker Telescope. Orbital elements are alsopresented for 14 systems, seven of which have had no previouslypublished orbital analyses.
| 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
| Apsidal Motion in Double Stars. I. Catalog
A catalog of 128 double stars with measured periods of apsidal motion iscompiled. Besides the apsidal periods, the orbital elements of binariesand physical parameters of components (masses, radii, effectivetemperatures, surface gravities) are given. The agreement of the apsidalperiods found by various authors is discussed.
| Colliding Winds in Massive Binary Systems
Not Available
| Massive stars
We describe the present state of massive star research seen from theviewpoint of stellar evolution, with special emphasis on close binaries.Statistics of massive close binaries are reasonably complete for theSolar neighbourhood. We defend the thesis that within our knowledge,many scientific results where the effects of binaries are not included,have an academic value, but may be far from reality. In chapter I, wesummarize general observations of massive stars where we focus on the HRdiagram, stellar wind mass loss rates, the stellar surface chemistry,rotation, circumstellar environments, supernovae. Close binaries can notbe studied separately from single stars and vice versa. First, theevolution of single stars is discussed (chapter I). We refer to newcalculations with updated stellar wind mass loss rate formalisms andconclusions are proposed resulting from a comparison with representativeobservations. Massive binaries are considered in chapter II. Basicprocesses are briefly described, i.e. the Roche lobe overflow and masstransfer, the common envelope process, the spiral-in process in binarieswith extreme mass ratio, the effects of mass accretion and the mergingprocess, the implications of the (asymmetric) supernova explosion of oneof the components on the orbital parameters of the binary. Evolutionarycomputations of interacting close binaries are discussed and generalconclusions are drawn. The enormous amount of observational data ofmassive binaries is summarized. We separately consider the non-evolvedand evolved systems. The latter class includes the semi-detached andcontact binaries, the WR binaries, the X-ray binaries, the runaways, thesingle and binary pulsars. A general comparison between theoreticalevolution and observations is combined with a discussion of speciallyinteresting binaries: the evolved binaries HD 163181, HD 12323, HD14633, HD 193516, HD 25638, HD 209481, Φ Per and silon Sgr; theWR+OB binary V444 Cyg; the high mass X-ray binaries Vela X-1, Wray 977,Cyg X-1; the low mass X-ray binaries Her X-1 and those with a black holecandidate; the runaway ζ Pup, the WR+compact companion candidatesCyg X-3, HD 50896 and HD 197406. We finally propose an overallevolutionary model of massive close binaries as a function of primarymass, mass ratio and orbital period. Chapter III deals with massive starpopulation synthesis with a realistic population of binaries. We discussthe massive close binary frequency, mass ratio and period distribution,the observations that allow to constrain possible asymmetries during thesupernova explosion of a massive star. We focuss on the comparisonbetween observed star numbers (as a function of metallicity) andtheoretically predicted numbers of stellar populations in regions ofcontinuous star formation and in starburst regions. Special attention isgiven to the O-type star/WR star/red supergiant star population, thepulsar and binary pulsar population, the supernova rates.
| A Survey for H alpha Emission in Massive Binaries: The Search for Colliding Wind Candidates
I report the results of the first all-sky survey of H alpha emission inthe spectra of O-type binaries. The survey includes 26 systems, of which10 have emission that extends clearly above the continuum. This is thefirst report of emission for four of these. An additional three systemsshow small distortions in the H alpha profile that may result from weakemission. I compare the distribution of emission systems in H-R diagramsfor both binary and single stars, using a survey of single O-type starsdone by Conti (1974). Emission in main-sequence systems is extremelyrare and is completely absent in my sample of binary stars. Among binarystars, 78% of the systems containing giants show some emission, while nosingle giants in Conti's sample do. In the case of supergiants, 78% ofsingle stars show emission, while all supergiant binaries show strongemission. H alpha emission may come from a variety sources, but the factthat binaries have a higher incidence and strength of emission inpost--main-sequence stages may indicate that wind interactions are acommon source of emission in massive binaries. To ascertain whether ornot colliding winds have been observed, it will be necessary to studythe H alpha line profile throughout several orbits of each candidatecolliding wind system and look for recurring orbital-phase--relatedvariations. Such a study is underway.
| Photospheric Heating in Colliding-Wind Binaries
The spectra of many massive binaries show secondary line depths that aredeeper when the secondary is approaching, a phenomenon we refer to asthe Struve-Sahade effect. Such systems are expected to contain collidingstellar winds, and we show how the X-ray flux from the bow shock thatwraps around the secondary will preferentially heat one hemisphere ofthe secondary. If the bow shock suffers any significant Coriolisdeflection due to orbital motion, then the heated surface of thesecondary will be best seen during orbital phases of secondary approach.We present model calculations for the system AO Cassiopeiae thatillustrate how the secondary's light curve appears brighter during theseorbital phases (as observed). We find that the model profiles ofspectral lines that are insensitive to or that strengthen with heatingwill appear deeper when the secondary is approaching, but the sameheating effects may be nulled or even reversed in lines that weaken withincreased temperature. This differing response of lines to heating maybe at odds with reports of systematic deepening of UV and optical lines,and thus the connection between such heating and the Struve-Sahadeeffect needs further observational and theoretical investigation.
| Cross-correlation characteristics of OB stars from IUE spectroscopy
We present a catalogue of homogeneous measures of the linewidthparameter, v_esin i, for 373 O-type stars and early B supergiants(including the separate components of 25 binary and three triplesystems), produced by cross-correlating high-resolution,short-wavelength IUE spectra against a `template' spectrum of tauSco. Wealso tabulate terminal velocities. There are no O supergiants in oursample with v_esin i<65 km s^-1, and only one supergiant earlier thanB5 has v_esin i<50 km s^-1, confirming that an important linebroadening mechanism in addition to rotation must be present in theseobjects. A calibration of the area under the cross-correlation peakagainst spectral type is used to obtain estimates of continuum intensityratios of the components in 28 spectroscopically binary or multiplesystems. At least seven SB2 systems show evidence for the `Struve-Sahadeeffect', a systematic variation in relative line strength as a functionof orbital phase. The stellar wind profiles of the most rapid rotator inour sample, the O9III:n* star HD 191423 (v_esin i=436km s^-1), show itto have a `wind-compressed disc' similar to that of HD 93521; this starand other rapid rotators are good candidates for studies of non-radialpulsation.
| Far-Ultraviolet Stellar Photometry: Fields Centered on rho Ophiuchi and the Galactic Center
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..104..101S&db_key=AST
| 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.
| SANTIAGO 91, a right ascension catalogue of 3387 stars (equinox J2000).
The positions in right ascension of 3387 stars belonging to the Santiago67 Catalogue, observed with the Repsold Meridian Circle at Cerro Calan,National Astronomical Observatory, during the period 1989 to 1994, aregiven. The average mean square error of a position, for the wholeCatalogue, is +/-0.009 s. The mean epoch of the catalogue is 1991.84.
| Far-ultraviolet stellar photometry: Fields in Sagittarius and Scorpius
Far-ultraviolet photometry for 741 objects in a field in Sagittariuscentered near M8 and 541 objects in a field centered near sigma Scorpiiis presented. These data were extracted from electographic imagesobtained with two cameras during a shuttle flight in 1991 April/May. Thecameras provided band passes with lambdaeff = 1375 A andlambdaeff = 1781 A. Synthetic colors show that these bandsare sensitive to effective temperature for hot stars. Our measurementswere placed on a quantitative far-ultraviolet magnitude scale byconvolving the spectra of stars observed by IUE with our cameras'spectral response functions. Fifty-eight percent of the ultravioletobjects were identified with visible stars using the SIMBAD databasewhile another 40% of the objects are blends of early type stars tooclose together to separate with our resolution. Our photometry iscompared with that from the TD-1, OAO 2, and ANS satellites and the S201(Apollo 16) far-ultraviolet camera and found to agree at the level of afew tenths of a magnitude. Unlike previous studies, almost half of theidentified visual counterparts to the ultraviolet objects are early Bstars. A plot of distance modulus against ultraviolet color excessreveals a significant population of stars with strong ultravioletexcess.
| "Doppler Tomography of O-Type Binary Systems"
The ability to gain information on the individual components of O-typebinary systems has been difficult because of the severe line blendingthat is present in these systems. Doppler tomography is an iterativescheme that uses an ensemble of spectra, uniformly distributed in phase,along with radial velocity curves to reconstruct the individualcomponent spectra (see Bagnuolo,Gies and Wiggs, 1992,ApJ,385,708). Theseindividual spectra can then be analyzed. The spectral types andluminosity classes obtained will provide indicators of the temperatureand gravity of the components. Also obtainable from the individualcomponent spectra are vsini of primary and secondary, a magnitudedifference estimate, and, potentially, abundance differences. The use ofIUE high dispersion spectra is optimal for O-type binary systems becauseof the presence of many lines in the UV. The high excitation of theselines also reduces the amount of contamination from interstellaremission. Radial velocity curves, which are necessary for the tomographyalgorithm, are refined by cross-correlation methods using standardspectra of appropriate spectral types. We are presently embarking upon alarge scale project involving 35 O-type binary systems with over 560spectra from the IUE. This paper presents initial radial velocity andtomographic results from 6 of these systems: D H Cep, HD 93403, HD152218, HD 152248, HD163181, and HD 165052. All are double linedspectroscopic binaries. They range from B0.5Iae to O5f in spectral classwith periods of 2.1 to 15.1 days.
| Evolution of massive close binaries
Not Available
| Massive close binaries - Observations and evolutionary computations
An overview of research on massive close binary (MCB) evolution in thelate seventies and eighties is presented, and the processes involved inmassive close binaries are explained. The following aspects of the MCBevolution study are considered: definition and types; observations ofnon-evolved and evolved MCB; physical processes; and stellar wind massloss rates and convective core overshooting. A comparison between MCBobservations and evolutionary computations is made. For futuredevelopments of stellar evolution, physical studies and the determinatonof adequate abundances of carbon, oxygen and nitrogen of stars coveringthe whole massive star range are recommended.
| Evolution of the primary components of massive binary stars in the case of Roche lobe overflow after main-sequence evolution
The evolution of primary components with 32 and 64 solar masses isstudied. Evolving with matter mixing in the semiconvective zone andfilling their Roche lobes, these components overflow their Roche lobesafter the main-sequence evolution and lose matter during the first partof helium core burning. After the end of the overflow, the componentslose their matter as a result of stellar wind and shrink in the nucleartimescale. At first, they have the characteristics of blue supergiantswith an anomalous CNO abundance, and then the features of the Wolf-Rayetstars.
| Fifth fundamental catalogue. Part 2: The FK5 extension - new fundamental stars
The mean positions and proper motions for 3117 new fundamental starsessentially in the magnitude range about 4.5 to 9.5 are given in thisFK5 extension. Mean apparent visual magnitude is 7.2 and is on average2.5 magnitudes fainter then the basic FK5 which has a mean magnitude of4.7. (The basic FK5 gives the mean positions and proper motions for theclassical 1535 fundamental stars). The following are discussed: theobservational material, reduction of observations, star selection, andthe system for the FK5 extension. An explanation and description of thecatalog are given. The catalog of 3117 fundamental stars for the equinoxand epoch J2000.0 and B1950.0 is presented. The parallaxes and radialvelocities for 22 extension stars with large forecasting effects aregiven. Catalogs used in the compilation of the FK5 fundamental catalogare listed.
| Close binaries observed polarimetrically
Not Available
| Photospheric Absorption Lines in the Ultraviolet Spectra of O-Stars and B-Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990MNRAS.246..392P&db_key=AST
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Scorpius |
| Right ascension: | 17h56m16.08s |
| Declination: | -32°28'30.0" |
| Apparent magnitude: | 6.605 |
| Distance: | 10000000 parsecs |
| Proper motion RA: | 2.7 |
| Proper motion Dec: | -0.4 |
| B-T magnitude: | 7.086 |
| V-T magnitude: | 6.645 |
Catalogs and designations:
|
INHABITED SKY
