Photoelectric Minima of Some Eclipsing Binary Stars
We present 119 minima times of 47 eclipsing binaries.
|
Masses and angular momenta of contact binary stars
Results are presented on component masses and system angular momenta forover 100 low-temperature contact binaries. It is found that thesecondary components in close binary systems are very similar in mass.Our observational evidence strongly supports the argument that theevolutionary process goes from near-contact binaries to A-type contactbinaries, without any need of mass loss from the system. Furthermore,the evolutionary direction of A-type into W-type systems with asimultaneous mass and angular momentum loss is also discussed. Theopposite direction of evolution seems to be unlikely, since it requiresan increase of the total mass and the angular momentum of the system.
|
BVR observations and period variation of the near-contact binary ZZ Aurigae
BVR light curves of ZZ Aurigae were obtained with the 60-cm Cassegrainreflector at the Sobaek Observatory, Korea, between 2000 February and2001 February. All collected times of minimum light, including ourobservations, were used for the period study. The period variation couldbe of quasi-sinusoidal form superposed on an upward parabola. Acontinuous period increase of dP/dt=+2.3 × 10-8 dyr-1 was determined for ZZ Aur. The period ofquasi-sinusoidal variation is about ~26-31 yr. Photometric solutionswere found using the Wilson-Devinney method. The Roche configuration ofZZ Aur is that of an Algol-type semidetached system where the primarystar nearly fills its Roche lobe and the secondary star fills its lobe.The spot model was used to explain the asymmetry in the light curveknown as the O'Connell effect.
|
Evolution of interacting binaries with a B type primary at birth
We revisited the analytical expression for the mass ratio distributionfor non-evolved binaries with a B type primary. Selection effectsgoverning the observations were taken into account in order to comparetheory with observations. Theory was optimized so as to fit best withthe observed q-distribution of SB1s and SB2s. The accuracy of thistheoretical mass ratio distribution function is severely hindered by theuncertainties on the observations. We present a library of evolutionarycomputations for binaries with a B type primary at birth. Some liberalcomputations including loss of mass and angular momentum during binaryevolution are added to an extensive grid of conservative calculations.Our computations are compared statistically to the observeddistributions of orbital periods and mass ratios of Algols. ConservativeRoche Lobe Over Flow (RLOF) reproduces the observed distribution oforbital periods but fails to explain the observed mass ratios in therange q in [0.4-1]. In order to obtain a better fit the binaries have tolose a significant amount of matter, without losing much angularmomentum.
|
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 Some Eclipsing Binary Stars
We present 70 minima times of 35 eclipsing binaries.
|
A near-contact binary: CN Andromedae
New BVR light curves and photometric analysis of the eclipsing binarystar CN And are presented. The shape of the light curves are typical ofβ Lyr type, and there are large asymmetries between maxima. The BVRlight curves and the radial velocity curves (from Rucinski et al. 2000)were solved with the Wilson-Devinney method, simultaneously. The resultssuggest that CN And is a almost contact binary system, in which thecomponent stars are filling 99% of their Roche lobes. We discussthe model with a large dark starspot on the more massive star and abright substellar spot on the companion to account for the light curveasymmetries. The absolute parameters of the system were also derived.The system resembles the near contact binary V1010 Oph according to itsRoche configuration and light curve asymmetries. We, also, discuss theevolution of the system: it seems to be in a transition phase to thecontact era. All previous times of minimum light were collected andcombined with the new ones presented in this work. The variation of theorbital period of the system was then analyzed. The results reveal thatthe orbital period has a secular decrease of about 1.98±0.04 secper century, which corresponds to a conservative mass transfer from themore to the less massive component at a rate of(1.52±0.09)×10-7m_ȯ/yr or a mass loss fromthe primary component due to magnetic stellar winds at a rate of(7.83±0.09)×10-8m_ȯ/yr.
|
Times of Minima of Eclipsing Binary Systems DO Cas, V1143 Cyg, GO Cyg, and VW Cep
11 photoelectric minima are presented from the observations of 4eclipsing binaries.
|
Beobachtungsergebnisse Bundesdeutsche Arbeitsgemeinschaft fur Veraenderliche Sterne e.V.
Not Available
|
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
|
Photoelectric Minima of Selected Eclipsing Binaries and New Elements for Several Stars
Not Available
|
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.
|
Period changes in W UMa-type eclipsing binaries: DK Cygni, V401 Cygni, AD Phoenicis and Y Sextantis
We present a period analysis of the four well-known W UMa-type eclipsingbinaries DK Cyg (P = 0fd47 ), V401 Cyg (0fd58 ), AD Phe (0fd38 ) and YSex (0fd42 ). Several new times of minimum light, recordedphotoelectrically, have been gathered. Analysis of all available eclipsetimings of the DK Cygni and V401 Cygni has confirmed a significantincrease in period of 1.15 10-10 and 1.48 10-10day cycle-1, respectively. A simultaneous solution of the B,V and R light curves was computed for V401 Cyg using the Binary Maker2.0 synthetic lightcurve software. This solution indicates that V401 Cygis in contact with a filing factor of 46%. The period of AD Phe seems tobe constant. Period changes of Y Sex could be explain by a light-timeeffect caused by a third body in an eccentric orbit with a period of 58years. Some of the observations reported in this paper were obtained atthe South Africa Astronomical Observatory, Sutherland, South Africa.
|
1998 UBV Observations of st Aquarii and Light Curve Analysis
1998 UBV photometry of short period eclipsing binary ST Aquarii havebeen presented. The photometric solution obtained from light curveanalysis by the method of differential corrections indicates that thesystem can be classified as a near contact binary. Derived value for theratio of radii left( {k = {left< {r_c } rightrangle }/{left< {r_hrightrangle }} \cong 0.67} right) shows that both components cannot beconsidered to be Main-Sequence, but they are probably evolved from M.S.
|
A Photometric study of EB-type eclipsing binary GO Cyg.
Not Available
|
Do the physical properties of Ap binaries depend on their orbital elements?
We reveal sufficient evidence that the physical characteristics of Apstars are related to binarity. The Ap star peculiarity [represented bythe Δ(V1-G) value and magnetic field strength] diminishes witheccentricity, and it may also increase with orbital period(Porb). This pattern, however, does not hold for largeorbital periods. A striking gap that occurs in the orbital perioddistribution of Ap binaries at 160-600d might well mark a discontinuityin the above-mentioned behaviour. There is also an interestingindication that the Ap star eccentricities are relatively lower thanthose of corresponding B9-A2 normal binaries for Porb>10d.All this gives serious support to the pioneering idea of Abt &Snowden concerning a possible interplay between the magnetism of Apstars and their binarity. Nevertheless, we argue instead in favour ofanother mechanism, namely that it is binarity that affects magnetism andnot the opposite, and suggest the presence of a newmagnetohydrodynamical mechanism induced by the stellar companion andstretching to surprisingly large Porb.
|
Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
Not Available
|
Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
Not Available
|
Photoelectric Minima of Eclipsing Binaries
Not Available
|
The GO Cygni system: a near contact eclipsing binary
The GO Cygni system is a short period -0.7177 days- eclipsing binarywith a % beta Lyrae-type light curve. In this study our new BVphotoelectric observations of the system, made at the BucharestObservatory during 1993-94 are presented. These, and our old ones -madeat the Kryonerion Astronomical Station of the National Observatory ofAthens, Greece, in 1985- are analysed using Wood's program. Thegeometrical elements of the system -derived from the present analysis-correspond to a contact configuration suggesting that it belongs to theso-called near contact binaries. Moreover, its physical parameters leadto an unevolved system with both of its components located very close tothe ZAMS. Finally, its orbital period is examined and found to showcontinuous increased.
|
Photometric Observations and Light Curves Analysis of GO Cygni
Photoelectric observations, in U, B and V, of the system GO Cygni wereobtained during 1995 at the Birouni Observatory, Shiraz, Iran, and thecorresponding light curves analysed with the use of Wilson-Devinney;'stechniques. New photoelectric and absolute elements for the system aregiven. The period of the system, a reverse Algol type semi-detachedbinary was found to continue its increasing.
|
Close Binary System GO Cygnus: Standard UBV Observations and Light Curve Analysis
Not Available
|
The calculation of critical rotational periods in three typical close binary systems based on synchronization theory.
Not Available
|
Photoelectric Minima of Selected Eclipsing Binaries
Not Available
|
Near-Contact Binary Systems in the ROSAT All-Sky Survey
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJ...461..951S&db_key=AST
|
Study of the eclipsing binary GO Cygni based on observations of Bucharest and Athens observatories from 1985 to 1994
The principal aim of this work is to study the eclipsing binary systemGO Cygni for which a series of photoelectric observations have beencarried out for ten years, 1985-1994, either at Athens or at theBucharest Observatories. The unpublished data obtained from 1989 to 1992are given and the corresponding light curves of the system are presentedwhile a general discussion concerning some of their features is made. Ashift of the order of 0.082 found in the V light curves of 1989-90 &92 and those of 1993-94 can be due to the variability of the comparisonstar BD+35°4197, which has to be checked; while some peculiarfeatures of its light curves may be due to the activity of the system.Moreover, the observed variations in the period of GO Cygni arediscussed.
|
Measurement and study of rotation in close binary stars (III) Statistical analysis of synchronization.
Not Available
|
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.
|
Photoelectric Maxima/minima of Selected Variables
Not Available
|
New Minima Times and Period Behaviour for the Eclipsing Variables RT Andromedae, 44i Bootis and GO Cygni
Not Available
|
INHABITED SKY
