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.
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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
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Survey of Hα Mass Transfer Structures in Classical Algol-Type Binaries
Five years of Hα survey data for 37 ``classical'' Algol-typebinaries are presented. All these systems have primaries with a spectraltype of A or B, have a period of less than 5 days, and are visible inthe Northern Hemisphere. Data were collected with the 1.02 m reflectorat the US Naval Observatory, Flagstaff Station. The survey consists ofover 460 system spectra. Each system was observed at least once duringthe 5 years, with many systems observed several times over severalepochs. Difference profiles are calculated for most spectra by modelingand subtracting the spectrum of the photospheres of the stellarcomponents. We examined each spectrum for the presence of mass transfer,stream-star and stream-disk interaction, a disk or circumstellar bulge,and chromospheric emission. We present information on the prevalence ofmass transfer activity, disk presence, and system states associated withparticular mass transfer structures. We show that no currently publishedstudy, including this one, has enough data for a rigorous statisticalidentification of system states.
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Photovisual Magnitude Differences for 169 Double Stars
Photovisual magnitude differences determined from multi-exposurephotographic plates for 169 double stars are presented. The separationsrange from 1.5'' to 113\arcsec, and the photovisual magnitudedifferences vary from 0.03 to 6.14 magnitudes. The internal mean errorof a single magnitude difference estimate is +/-0.064 magnitude.
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Mass Flow in the Close Binary V342 Aquilae
Preliminary analysis of the eclipsing binary V342 Aquilae indicates itis undergoing an extremely active phase of mass flow. Threeobservational datasets provide complete orbital phase coverage of the3.39 day period across a wide band; IUE spectroscopic data, photometricuvbyRI data, and optical spectroscopy data. IUE observations made in1991, 1993 and 1995 include 88 low resolution SWP and LWP spectraspanning from 1150 to 3200 Angstroms. The uvbyRI optical photometry data(P. Etzel) were obtained simultaneously with the 1993 IUE observations.Limited KPNO 2.1 meter telescope optical data (A. Welty) covering from3840 to 9000 Angstroms were taken in 1994. Our UV spectra show verypronounced Fe II absorption lines arising from ground and metastablelevels, indicating an extensive circumstellar shell in the system. Thestrength of this absorption shows both an orbital and a cycle-to-cyclevariability. The eclipse spectra display very strong emission from linessuch as C II at 1335 Angstroms, Si IV at 1400 Angstroms, and C IV at1550 Angstroms, with a striking similarity to the eclipse spectra of TTHydrae. Based upon these data, we have deduced the effectivetemperatures, spectral types and orbital geometry of the two stars. TheUV spectra show the primary is approximately a late B star and thesecondary is a late G star. We also present velocity curve results fromthe optical data along with the resulting mass ratio estimate. Ourongoing analysis aims to understand the unusually large rate of massflow occuring in V342 Aquilae. P.B.E. acknowledges support under NSFgrant AST-9115104.
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The Close Binary V342 Aquilae: A System Undergoing Extremely Active Mass Transfer
Preliminary analysis of the eclipsing binary V342 Aquilae indicates itis undergoing an extremely active phase of mass transfer. This is seenin our comprehensive data set consisting of both IUE spectroscopic andphotometric uvbyri data, providing complete orbital phase coverage ofthe 3.39 day period. IUE observations made in 1991, 1993 and 1995include 65 low resolution SWP and LWP spectra providing spectralcoverage from 1150 to 3200 Angstroms. Besides variable Hα emissionseen in the optical, our UV spectra show very pronounced FeII absorptionlines arising from ground and metastable levels, indicating an extensivecircumstellar shell in the system. The strength of this absorptionvaries significantly over orbital phase. The eclipse spectra show verystrong emission from lines such as CII at 1335 Angstroms, Si IV at 1400Angstroms, and CIV at 1550 Angstroms. The UV spectra clearly show thatthe primary is earlier than B8. The effective temperatures, spectraltypes and orbital geometry of the two stars, as well as the propertiesof the surrounding circumstellar envelope and the eclipse spectra willbe discussed. Our ongoing analysis aims to understand the unusuallylarge rate of mass flow occuring in V342 Aquilae. P.B.E acknowledgessupport under NSF grant AST-9115104.
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Rapid H-alpha emission variations in accretion disks in long-period ALGOLS
We demonstrate the continuous presence of large variations indouble-peaked H-alpha long period Algol-type binaries, using recentlyobtained CCD spectra. Most fluctuations occur on a time scale less thanor = an orbital period and a steady state in H-alpha emission ia neverreached. In AD Her (P = 10 d), H-alpha emission dropped in strength morethan a factor of five in one seven-day interval. Contemporay O I lambdaobservations showed no significant changes in oxygen absorption strengthor radial velocity during this time. We tentatively suggest that H-alphavariations arise from an inner-disk instability, possibly triggered bysmall modulations in the mass-transfer rate. This behavior isreminiscent of some cataclysmic variables.
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O I lamba 7774 absorption as a tracer of streams and disks in nondegenerate binary stars
We propose a new spectroscopic approach for observing circumstellarmatter in binary stars, based on the neutral oxygen lambda 7774absorption lines. We present oxygen equivalent widths and radialvelocities in 20 nondegenerate eclipsing binaries. We note limitationsand advantages of using this line to trace circumstellar matter inbinary systems, and confirm the presence of streams and rotatingaccretion disks in a number of short- long-period Algol systems. Wediscuss evidence for geometrically thick disks, and describe a smallradial infall superimposed on disk rotation in most long-period systems.We speculate that infall may be related to viscous dissipation in disks.We emphasize the great sensitivity of lambda 7774 in studying thekinematics of circumstellar matter in many nondegenerate binary stars.
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New rotational velocities for eclipsing binaries, and a comparison of spectroscopic and photometric rotations
Rotational velocities are determined spectroscopically for 38 eclipsingbinaries, including many long-period, nominally semidetached, systems.We note that spectroscopic rotations may differ from rotations derivedfrom light-curve modeling using the Wilson-Devinney program. In'direct-impact' mass-transferring systems, or in most systems withperiods smaller than about 7 days, observations suggest that the tworotations are usually about the same. In cases where the stream missesthe gainer and an accretion disk forms, however, photometric rotationestimates often exceed spectroscopic determinations. The possiblephysical significance of this situation is briefly discussed. Doubt iscast on the likelihood that the rotation of the hot component of U Sgehas changed detectably in the last 30 years.
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Spectroscopy of V342 Aquilae
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Maximum separations among cataloged binaries
The paper classifies many of the widest common-motion binaries listed inthe Aitken catalog and list 72 physical pairs with known photoelectricphotometry, 31 physical pairs without good photometry, and 27 opticalpairs. As a function of primary types, the physical systems have upperlimits to their separations that are exceeded by some of the opticalpairs. The fact that optical pairs occur with larger separations impliesthat the limits are real ones and not just catalog limitations. Thoselimits (in AU) are expressed by 2500 M1 exp 1.54 for B5-KO main-sequenceprimaries. The same limits hold for the Trapezium and hierarchicalsystems studied previously.
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A Catalogue of Classical Evolved Algol-Type Binary Candidate Stars
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Statistics of categorized eclipsing binary systems Lightcurve shapes, periods, and spectral types
The statistics of the light curve morphologies, eclipse depths, orbitalperiods, and spectral types of about 1000 eclipsing binary systems areexamined, after attempting to subdivide these binaries into variousbasic evolutionary categories. The applicability of statisticalcriteria, based on light curve morphologies and eclipse depths, for thecategorization of eclipsing binaries has been found more limited thanpreviously believed. In particular, EW-type light curves turn out to begood indicators of contact systems (though not conversely), while EA-and EB-type light curves have little physical significance. Moreover,the study reveals a strong deficit of short-period noncontact systems inthe whole spectral range, together with an underabundance of early-typecontact binaries (compared with the number of late-type contact pairs).Interestingly, the distribution of evolved Algol-type systems isshifted, on average, to periods longer than those of unevolved detachedsystems in the OB and early A spectral range (and to shorter periods inthe F spectral range).
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A catalogue of variable-visual binary stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1981A&AS...44..179P&db_key=AST
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A catalogue of parameters for eclipsing binaries
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Cyanogen strengths, mixing and supermetallicity in G and K giants
Wide visual binaries consisting of a G or K giant in physicalassociation with an F dwarf, observed using DDO and ubvy photometry,were used to study the possibility of mixing in the giants prior to orduring helium core burning. The two abundance indices, delta m1 of theuvby system, and delta CN of the DDO system, are compared to study thepossibility that mixing from a hydrogen burning region has affected theCN strengths of the giants.
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Minima of Eclipsing Variables (XI)
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UBV photometry of eclipsing binaries with visual companions
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971PASP...83...69H&db_key=AST
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Minima of Eclipsing Variables
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Minima of Eclipsing Variables
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Minima of Eclipsing Variables
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A Possible Major Period Change in V342 Aquilae
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Catalogue d'étoiles doubles ayant une composante variable
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A study of visual binaries having primaries above the main sequence.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960AJ.....65...60S&db_key=AST
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Benennung von veränderlichen Sternen
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162 neue Veräderliche
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INHABITED SKY
