The Case for Third Bodies as the Cause of Period Changes in Selected Algol Systems
Many eclipsing binary star systems show long-term variations in theirorbital periods, evident in their O-C (observed minus calculated period)diagrams. With data from the Robotic Optical Transient Search Experiment(ROTSE-I) compiled in the SkyDOT database, New Mexico State University 1m data, and recent American Association of Variable Star Observers(AAVSO) data, we revisit Borkovits and Hegedüs's best-casecandidates for third-body effects in eclipsing binaries: AB And, TV Cas,XX Cep, and AK Her. We also examine the possibility of a third bodyorbiting Y Cam. Our new data support their suggestion that a third bodyis present in all systems except AK Her, as is revealed by thesinusoidal variations of the O-C residuals. Our new data suggest that athird body alone cannot explain the variations seen in the O-C residualsof AK Her. We also provide a table of 143 eclipsing binary systems thathave historical AAVSO O-C data with new values computed from the SkyDOTdatabase.
|
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.
|
Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
Not Available
|
Beobachtungssergebnisse Bundesdeutsche Arbeitsgemeinschaft fuer Veraenderliche Sterne e.V.
Not Available
|
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
|
Beobachtungsergebnisse Bundesdeutsche Arbeitsgemeinschaft fur Veranderlichen Serne e.V.
Not Available
|
Photoelectric Minima of Selected Eclipsing Binaries
Not Available
|
Archive of Photometric Plates Obtained at Cluj Astronomical Observatory
The archive of photometric plates obtained at the AstronomicalObservatory of Cluj in the period 1952-1974 is presented. The plateinventory is made within the framework of the Wide-Field Plate Databaseproject. The plates were taken in the regions around 110 variable stars(eclipsing variables and RR Lyrae-type stars), as well as in somecomparison stars regions.
|
uvbyβ Photometry of Selected Eclipsing Binary Stars
New uvbyβ observations of 51 eclipsing binary stars are presented,and outside-eclipse averages for 45 of them are given. Many of thesebinaries are detached main-sequence pairs that have been discovered tobe double-lined spectroscopic binaries and appear suitable fordeterminations of accurate absolute dimensions and masses. Photometricproperties are recomputed for 14 of the binaries, for which absoluteproperties have been published previously. Intercomparisons are madewith previous photometry, when available, and notes are given for someindividual systems.
|
Times of Minima of Eclipsing Binaries
Not Available
|
149 Bedeckungssterne der BAV-Programme. Eine Analyse der Beobachtungstatigkeit seit den Angangen.
Not Available
|
Das Brunner Punktesystem.
Not Available
|
Times of Minima of Eclipsing Binaries
Not Available
|
Beobachtungsergebnisse Bundesdeutsche Arbeitsgemeinschaft fur Veraenderliche Sterne e.V.
Not Available
|
Times of Minima of Eclipsing Binaries
Not Available
|
Photoelectric Minima and Maxima of Selected Eclipsing and Pulsating Variables
Not Available
|
Photoelectric Minima of Eclipsing Binaries
Not Available
|
Predicting the Secondary Minima Depths and Spectra of the Main Components for the Dm-Type Eclipsing Variable Stars
Not Available
|
Searching for Intrinsic Variations in Eclipsing Binary Stars
Using a database of nearly 4000 visual estimates made by the authorbetween 1967 and 1993, evidence for intrinsic variations on a time scaleof years is sought after 64 eclipsing binary stars. While none is foundfor most stars, certainb objects warrant further investigation.
|
UBV photometry of selected eclipsing binary stars
The study reports new UBV observations of 69 eclipsing binary stars andprovides outside-eclipse averages. Revised photometric properties offive of the binaries, for which absolute properties were publishedpreviously, are computed. Comparisons are made with previous photometry,when available, and notes are given for some individual systems.
|
Photoelectric Minima of Eclipsing Binaries
Not Available
|
An Updated List of Eclipsing Binaries Showing Apsidal Motion
Not Available
|
Properties of the main-sequence eclipsing binary KP Aquilae
Radial velocities and line profiles of KP Aql (F0 + F0) are analyzed,and the results are combined with those of the light-curve analysis ofIbanoglu and Gulmen (1974) to yield absolute properties of thismain-sequence binary. Comparison of the properties of these stars withtheoretical models of stellar evolution indicates an age ofapproximately 8 x 10 to the 8th yr.
|
A Catalogue of Classical Evolved Algol-Type Binary Candidate Stars
Not Available
|
The period distribution of unevolved close binary systems
Period distributions have been examined for various spectral types ofabout 600 (eclipsing and spectroscopic) close binaries, which are likelyto be substantially unevolved. The comparison with the previouscorresponding analyses of extensive (but heterogeneous) binary samplesallows a clarification of the extent of the evolutionary andobservational selection effects. Remarkably, this analysis reveals agreat deficiency of short period binaries (with periods corresponding tocase A mass transfer) in the whole spectral range. For the late spectraltypes, this result may be connected with postformation angular momentumloss caused by stellar wind magnetic braking; at least for the late Band A spectral range, a ready interpretation of this finding is thatclose binaries of corresponding periods and spectral types are rarelyformed.
|
The q-log P distribution of classical ALGOLS
Data on a large sample (approximately 400) of candidates for theclassical Algol-type eclipsing binary configurations have beencollected. The mass-ratio q has been calculated on the assumption oftheir semi-detached nature, and then compared with corresponding periodfor some subsets of the sample. The tendency to slight overluminosity(compared with corresponding MS stars) of the primaries in classicalAlgols is confirmed. The role of the loss of angular momentum inclassical Algol evolution is considered, together with a method fordetermining representative parameters to characterize such effects usingthe sample data. The possible existence of a class of post-contactclassical Algols is noted.
|
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).
|
YZ CAS + or - 0.5 percent
The physical properties and orbit of the eclipsing binary YZ Cas arecalculated on the basis of spectroscopic radial-velocity determinationsobtained using the Reticon array on the 2.1 and 2.7-m telescopes atMcDonald Observatory during 1978-1981. Signal to-noise ratios of about500 were achieved during 30-min scans. The fitted spectroscopic orbit isshown, and the physical properties are listed in a table. The maximumradial-velocity accuracy obtainable with the Reticon is estimated as 0.5km/sec, and the higher accuracy claimed for devices usingradial-velocity masks is questioned: blended lines in double-linedbinaries could lead to systematic errors which would require carefulquantitative evaluation using computer simulations. The current statusof further eclipsing-binary studies using the Reticon is reviewed.
|
A catalogue of parameters for eclipsing binaries
Not Available
|
New Eclipsing Binary Results Obtained with a Reticon Detector
Not Available
|
