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Photometric study of neglected eclipsing binary GSC 3576-0170
The new multi-color BVRI photometric light curves of the short-periodeclipsing binary GSC 3576-0170 were obtained on two consecutive nights(October 5 and 6, 2009). With the 2003 version of Wilson–Devinneyprogram, the precise photometric solutions are derived for the firsttime. The result shows that GSC 3576-0170 is a semi-detached binarysystem with a large temperature difference of approximately 1490 K. Thelight-curve distortions are further explained by a hot spot on thesecondary component through mass transfer via a stream hitting thefacing surface of the secondary component. By analyzing all availablelight minimum times, we also derived an update ephemeris and found forthe first time a possible periodic oscillation with an amplitude of0.0038 days and a period of 4.3 years. The periodic oscillation could beexplained either by the light-time effect due to a presumed thirdcomponent or by magnetic activity cycle of the system.
| The V-band Empirical Mass-luminosity Relation for Main Sequence Stars
Stellar mass is an indispensable parameter in the studies of stellarphysics and stellar dynamics. On the one hand, the most reliable way todetermine the stellar dynamical mass is via orbital determinations ofbinaries. On the other hand, however, most stellar masses have to beestimated by using the mass luminosity relation (MLR). Therefore, it isimportant to obtain the empirical MLR through fitting the data ofstellar dynamical mass and luminosity. The effect of metallicity canmake this relation disperse in the V-band, but studies show that this ismainly limited to the case when the stellar mass is less than0.6M? Recently, many relevant data have been accumulatedfor main sequence stars with larger masses, which make it possible tosignificantly improve the corresponding MLR. Using a fitting methodwhich can reasonably assign weights to the observational data includingtwo quantities with different dimensions, we obtain a V-band MLR basedon the dynamical masses and luminosities of 203 main sequence stars. Incomparison with the previous work, the improved MLR is statisticallysignificant, and the relative error of mass estimation reaches about 5%.Therefore, our MLR is useful not only in the studies of statisticalnature, but also in the studies of concrete stellar systems, such as thelong-term dynamical study and the short-term positioning study of aspecific multiple star system.
| The CCD photometric study of the newly identified RS CVn binary star DV Piscium
This paper presents new CCD BVRI light curves of the newly discovered RSCVn eclipsing binary star DV Psc. From the asymmetric light curvesoutside the eclipse, we find there are two depressions in the phaseranges 0.3-0.45 and 0.6-0.9, respectively. By analyzing thelight curves using the Wilson-Devinney program, the fourphotometric solutions of the system are obtained and the starspotparameters are also derived. It turns out that the case of two spotsbeing on the primary is most successful in reproducing the light curvedistortion of DV Psc. Moreover, analysis the longitudes of spotssuggests that there are two active longitude belts (one is about90°, the other is about 270°). At the same time, on 22 November2008, the first flare-like event was detected on DV Psc at phase 0.35whose duration was about 13.5 min. These findings reveal that DV Psc hasa high degree of magnetic activity.
| The First Multicolor Photometric Study of the Eclipsing Binary KQ Gem
This paper presents the first multicolor photometry of the neglectedeclipsing binary KQ Gem. The light curves were obtained at the XinglongStation of the National Astronomical Observatories, China in twoobserving runs: 2008 November 24-27, and 2008 December 31. With the 2003version of the Wilson-Devinney program, these data were analyzedtogether with a light curve and some spectroscopic observationsobtained by Hilditch and colleagues in 1992. Photometric solutions of KQGem are derived on the basis of the hot-spot model due to mass transfervia a stream hitting the facing surface of the secondary component. Ourresult confirms that KQ Gem is a marginal-contact binary system with alarge temperature difference of about 1859 K between the two components.There is little variation among the curves from the three runs. Thisindicates a small variability for the hot spots on both a short and longtime scale. Furthermore, the first orbital period analysis shows aprobable period decrease based on all available primary times of lightminimum, which could be explained by mass transfer or by magneticbraking. As the period decreases, KQ Gem will contact again and evolveinto an overcontact system.
| Accurate masses and radii of normal stars: modern results and applications
This article presents and discusses a critical compilation of accurate,fundamental determinations of stellar masses and radii. We haveidentified 95 detached binary systems containing 190 stars (94 eclipsingsystems, and ? Centauri) that satisfy our criterion that the massand radius of both stars be known within errors of ±3% accuracyor better. All of them are non-interacting systems, and so the starsshould have evolved as if they were single. This sample more thandoubles that of the earlier similar review by Andersen (Astron AstrophysRev 3:91-126, 1991), extends the mass range at both ends and, forthe first time, includes an extragalactic binary. In every case, we haveexamined the original data and recomputed the stellar parameters with aconsistent set of assumptions and physical constants. To these we addinterstellar reddening, effective temperature, metal abundance,rotational velocity and apsidal motion determinations when available,and we compute a number of other physical parameters, notably luminosityand distance. These accurate physical parameters reveal the effects ofstellar evolution with unprecedented clarity, and we discuss the use ofthe data in observational tests of stellar evolution models in somedetail. Earlier findings of significant structural differences betweenmoderately fast-rotating, mildly active stars and single stars, ascribedto the presence of strong magnetic and spot activity, are confirmedbeyond doubt. We also show how the best data can be used to testprescriptions for the subtle interplay between convection, diffusion,and other non-classical effects in stellar models. The amount andquality of the data also allow us to analyse the tidal evolution of thesystems in considerable depth, testing prescriptions of rotationalsynchronisation and orbital circularisation in greater detail thanpossible before. We show that the formulae for pseudo-synchronisation ofstars in eccentric orbits predict the observed rotations quite well,except for very young and/or widely separated stars. Deviations dooccur, however, especially for stars with convective envelopes. Thesuperior data set finally demonstrates that apsidal motion rates aspredicted from General Relativity plus tidal theory are in goodagreement with the best observational data. No reliable binary dataexist, which challenge General Relativity to any significant extent. Thenew data also enable us to derive empirical calibrations of M and R forsingle (post-) main-sequence stars above {0.6 M_{odot}}. Simple,polynomial functions of T eff, log g and [Fe/H] yield M and Rwithin errors of 6 and 3%, respectively. Excellent agreement is foundwith independent determinations for host stars of transiting extrasolarplanets, and good agreement with determinations of M and R from stellarmodels as constrained by trigonometric parallaxes and spectroscopicvalues of T eff and [Fe/H]. Finally, we list a set of 23interferometric binaries with masses known to be better than 3%, butwithout fundamental radius determinations (except ? Aur). Wediscuss the prospects for improving these and other stellar parametersin the near future.
| Cyclic Variations of Orbital Period and Long-Term Luminosity in Close Binary RT Andromedae
Solutions of standard VR light curves for the eclipsing binary RT Andwere obtained using the PHOEBE program (ver. 0.3a). Absolute parametersof the stellar components were then determined, enabling them to bepositioned on the mass-luminosity diagram. Times of minima data ("O- C curve") were analyzed using the method of Kalimeris et al. Acyclic variation in the orbital period and brightness, with timescalesof about 11.89 and 12.50 yr were found, respectively. This is associatedwith a magnetic activity cycle modulating the orbital period of RT Andvia the Applegate mechanism. To check the consistency of the Applegatemodel, we have estimated some related parameters of the RT And system.The calculated parameters were in accordance with those estimated byApplegate for other similar systems, except B, the subsurface magneticfield of which shows a rather high value for RT And.
| XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources
The 18,806 ROSAT All Sky Survey Bright Source Catalog (RASS/BSC) X-raysources are quantitatively cross-associated with near-infrared (NIR)sources from the Two Micron All Sky Survey Point Source Catalog(2MASS/PSC). An association catalog is presented, listing the mostlikely counterpart for each RASS/BSC source, the probability Pid that the NIR source and X-ray source are uniquelyassociated, and the probability P no-id that none of the2MASS/PSC sources are associated with the X-ray source. The catalogincludes 3853 high quality (P id>0.98) X-ray-NIR matches,2280 medium quality (0.98 >= P id>0.9) matches, and4153 low quality (0.9 >= P id>0.5) matches. Of the highquality matches, 1418 are associations that are not listed in the SIMBADdatabase, and for which no high quality match with a USNO-A2 opticalsource was presented for the RASS/BSC source in previous work. Thepresent work offers a significant number of new associations withRASS/BSC objects that will require optical/NIR spectroscopy forclassification. For example, of the 6133 P id>0.92MASS/PSC counterparts presented in the association catalog, 2411 haveno classification listed in the SIMBAD database. These 2MASS/PSC sourceswill likely include scientifically useful examples of known sourceclasses of X-ray emitters (white dwarfs, coronally active stars, activegalactic nuclei), but may also contain previously unknown sourceclasses. It is determined that all coronally active stars in theRASS/BSC should have a counterpart in the 2MASS/PSC, and that the uniqueassociation of these RASS/BSC sources with their NIR counterparts thusis confusion limited.
| Absolute dimensions of solar-type eclipsing binaries. II. V636 Centauri: A 1.05 {M}ȯ primary with an active, cool, oversize 0.85 {M}ȯ secondary
Context: The influence of stellar activity on the fundamental propertiesof stars around and below 1 Mȯ is not well understood.Accurate mass, radius, and abundance determinations from solar-typebinaries exhibiting various levels of activity are needed for a betterinsight into the structure and evolution of these stars. Aims: Weaim to determine absolute dimensions and abundances for the solar-typedetached eclipsing binary V636 Cen, and to perform a detailed comparisonwith results from recent stellar evolutionary models. Methods:uvby light curves and uvbyβ standard photometry were obtained withthe Strömgren Automatic Telescope, radial velocity observationswith the CORAVEL spectrometer, and high-resolution spectra with theFEROS spectrograph, all at ESO, La Silla. State-of-the-art methods wereapplied for the photometric and spectroscopic analyses. Results:Masses and radii that are precise to 0.5% have been established for thecomponents of V636 Cen. The 0.85 Mȯ secondary componentis moderately active with starspots and Ca ii H and K emission, and the1.05 Mȯ primary shows signs of activity as well, but ata much lower level. We derive a [Fe/H] abundance of -0.20 ± 0.08and similar abundances for Si, Ca, Ti, V, Cr, Co, and Ni. Correspondingsolar-scaled stellar models are unable to reproduce V636 Cen, especiallyits secondary component, which is ~10% larger and ~400 K cooler thanpredicted. Models adopting significantly lower mixing-length parametersl/Hp remove these discrepancies, seen also for othersolar-type binary components. For the observed [Fe/H], Claret models forl/Hp = 1.4 (primary) and 1.0 (secondary) reproduce thecomponents of V636 Cen at a common age of 1.35 Gyr. The orbit iseccentric (e = 0.135 ± 0.001), and apsidal motion with a 40%relativistic contribution has been detected. The period is U = 5 270± 335 yr, and the inferred mean central density concentrationcoefficient, log(k_2) = -1.61 ± 0.05, agrees marginally withmodel predictions. The measured rotational velocities, 13.0 ± 0.2(primary) and 11.2 ± 0.5 (secondary) km s-1, are inremarkable agreement with the theoretically predicted pseudo-synchronousvelocities, but are about 15% lower than the periastron values. Conclusions: V636 Cen and 10 other well-studied inactive and activesolar-type binaries suggest that chromospheric activity, and its effecton envelope convection, is likely to cause radius and temperaturediscrepancies, which can be removed by adjusting the model mixing lengthparameters downwards. Noting this, the sample may also lend support totheoretical 2D radiation hydrodynamics studies, which predict a slightdecrease of the mixing length parameter with increasing temperature/massfor inactive main sequence stars. More binaries are, however, needed fora description/calibration in terms of physical parameters and level ofactivity.Based on observations carried out at the Strömgren AutomaticTelescope (SAT), the Danish 1.54 m telescope, and the 1.5 m telescope(62.L-0284) at ESO, La Silla, Chile. Table A.1 is only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/502/253
| Bericht zur 5. Veraenderlichen-beobachtungswoche an der VdS-sternwarte in kirchheim.
Not Available
| B.R.N.O. Times of minima
Not Available
| Absolute Properties of the Spotted Eclipsing Binary Star CV Boötis
We present new V-band differential brightness measurements as well asnew radial-velocity measurements of the detached, circular, 0.84 dayperiod, double-lined eclipsing binary system, CV Boo. These data, alongwith other observations from the literature, are combined to deriveimproved absolute dimensions of the stars for the purpose of testingvarious aspects of theoretical modeling. Despite complications fromintrinsic variability that we detect in the system, and despite therapid rotation of the components, we are able to determine the absolutemasses and radii to better than 1.3% and 2%, respectively. We obtain MA = 1.032 ± 0.013 M sun and R A= 1.262 ± 0.023 R sun for the hotter, larger, andmore-massive primary (star A), and M B = 0.968 ± 0.012M sun and R B = 1.173 ± 0.023 Rsun for the secondary. The estimated effective temperaturesare 5760 ± 150 K and 5670 ± 150 K, respectively. Theintrinsic variability with a period ~1% shorter than the orbital periodis interpreted as being due to modulation by spots on one or bothcomponents. This implies that the spotted star(s) must be rotatingfaster than the synchronous rate, which disagrees with predictions fromcurrent tidal evolution models according to which both stars should besynchronized. We also find that the radius of the secondary is largerthan expected from stellar evolution calculations by ~10%, a discrepancyalso seen in other (mostly lower-mass and active) eclipsing binaries. Weestimate the age of the system to be approximately 9 Gyr. Bothcomponents are near the end of their main-sequence phase, and theprimary may have started the shell hydrogen-burning stage.
| A catalogue of chromospherically active binary stars (third edition)
The catalogue of chromospherically active binaries (CABs) has beenrevised and updated. With 203 new identifications, the number of CABstars is increased to 409. The catalogue is available in electronicformat where each system has a number of lines (suborders) with a uniqueorder number. The columns contain data of limited numbers of selectedcross references, comments to explain peculiarities and the position ofthe binarity in case it belongs to a multiple system, classicalidentifications (RS Canum Venaticorum, BY Draconis), brightness andcolours, photometric and spectroscopic data, a description of emissionfeatures (CaII H and K, Hα, ultraviolet, infrared),X-ray luminosity, radio flux, physical quantities and orbitalinformation, where each basic entry is referenced so users can go to theoriginal sources.
| Chromospheric activity on the RS Canum Venaticorum binary SZ Piscium
Aims. We present the new high-resolution echelle spectra of SZ Psc,obtained in Nov. 2004 and Sep.-Dec. 2006, and study its chromosphericactivity. Methods: By means of the spectral subtraction technique, weanalyze our spectroscopic observations including several opticalchromospheric activity indicators (the He I D{3}, Na I D{1}, D{2},Hα, and Ca II infrared triplet lines). Results: All indicatorsshow that the chromospheric activity of the system is associated withthe cooler component. We find that the values ofEW8542/EW8498 are in the range 1-3, whichindicates optically thick emission in plage-like regions. The 2006 datasuggest the presence of active longitude phenomena. For the Ca II 8542and 8662 and the Hα lines, it seems that the excess emission isstronger near the two quadratures of system. This may be anti-correlatedwith the behavior of the Na I D{1} line. The absorption features aredetected in the subtracted Hα lines, which could be explained byprominence-like extended material seen on the stellar disk or by masstransfer from the cooler component to the hotter one.
| On the Period Variations of BH Virginis
In the present work, 17 new times of the light minimum for BHVir werederived from observations by Kjurkchieva etal. (2004, A&A, 424,993). Combining the new determined eclipse times with others compiledfrom the literature, the behavior of their O-C variation wasinvestigated. It has been found that the orbital period of BHVir showssome cyclic variations with three different periods: a long-periodvariation of 51.7years, and two short-period variations of 9.2years and11.8years, respectively. The mechanisms that could explain the periodchanges of the system are discussed.
| New absolute magnitude calibrations for detached binaries
Lutz-Kelker bias corrected absolute magnitude calibrations for thedetached binary systems with main-sequence components are presented. Theabsolute magnitudes of the calibrator stars were derived at intrinsiccolours of Johnson-Cousins and 2MASS (Two Micron All Sky Survey)photometric systems. As for the calibrator stars, 44 detached binarieswere selected from the Hipparcos catalogue, which have relative observedparallax errors smaller than 15% (σπ/π≤0.15).The calibration equations which provide the corrected absolute magnitudefor optical and near-infrared pass bands are valid for wide ranges ofcolours and absolute magnitudes: -0.18<(B-V)0<0.91,-1.6
| Mass-luminosity relation of intermediate-mass stars
The mass-luminosity relation (MLR) for intermediate-mass stars is basedon data on detached double-lined eclipsing binaries. However, there is anotable difference between the parameters of B0V-G0V components ofeclipsing binaries and those of single stars. Single early-type starsare rapid rotators, whereas tidal forces produce synchronous rotation inclose binaries and all such pairs are synchronized, so components ofclose binaries rotate more slowly. As is well known, stellar rotationchanges stellar evolution and the global parameters of a star.In this work we collect data on fundamental parameters of stars withmasses m > 1.5msolar. They are components of binaries withP > 15 d and consequently are not synchronized with the orbitalperiods and presumably are rapid rotators. These stars are believed toevolve similarly with single stars. Modern data on masses, absolute andbolometric luminosities, radii and temperatures of detachedmain-sequence double-lined eclipsing binary components (i.e. presumablyslow rotators) are also collected.Mass-luminosity, mass-temperature and mass-radius relations of close andwide binaries are presented, as well as their Hertzsprung-Russelldiagram. For the mass range 4.5 < m/msolar < 5.5 (lateB stars) it was found that rapid rotators exhibit slightly higherluminosities and larger radii than predicted by the standard relations,and their main sequence is shifted to the right-hand side with respectto that of the close binary components. The resulting relations forrapidly and slowly rotating A-F and early B stars are not statisticallydifferent.As our estimations show, for the given mass range the effect on theinitial mass function (IMF) is marginal, but there is no way to estimatethe degree to which the effect may be important for higher masses.Available observational data for m > 12msolar are too poorto make definite conclusions. Knowledge of the MLR should come fromdynamical mass determinations of visual binaries combined with spatiallyresolved precise photometry. Then the IMF should be revised for thatmass range.
| B.R.N.O. Contributions #34
Not Available
| Photometric study of the short-period RS Canum Venaticorum binary RT Andromedae
Context: Long-term photometric observations of cool stars can reveal theevolution and activity cycles of the stellar active region. Furthermore,studying the stellar activity provides opportunities for understandingof stellar dynamo and valuable constraints for stellar dynamo theory.Aims: We analyze our observational data and discuss light-curvevariability due to starspots on both a short and long time scale,especially the short-term variation. At the same time, we accumulatesome results from the literature to discuss active-region evolution andactivity cycles. Methods: By analyzing the light curves using theWilson-Devinney program, the photometric solution of the system isobtained and the starspot parameters are also derived. Using thephase-dispersion minimization method, we infer the activity cycle of RTAnd. Results: The case of two spots being on the primary is mostsuccessful in reproducing the light curve distortion of RT And in 2004.Although the light curves in 1999 and 2005 do not have sufficient phasecoverage, we still could use the spot model to explain their light-curvevariation successfully based on the photometric solution in 2004.Comparing the light curves of 1999, 2004, and 2005, the light curvedistortion changes on both short and long time scales, especially thesignificant variation around the secondary minimum on a time scale oftwo months. Analysis of the longitude of spots within the belt around270° suggests that the activity cycle of RT And may be 6.69 ±0.80 years.Table 1 is only available in electronic form at http://www.aanda.org
| Visual Minima Timings of Eclipsing Binaries Observed in the Years 1992 - 1996
The paper contains a list of 283 new times of minima and 77 revisedtimes of minima for 63 eclipsing binaries derived by the author fromhis visual observations.
| Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
Not Available
| New Times of Minima of Some Eclipsing Binary Stars
Not Available
| Precise Times of Minimum Light of Neglected Eclipsing Binaries
Not Available
| Veraenderlichen-Beobachtungswoche an der Sternwarte Kirchheim 2007.
Not Available
| Dynamical evolution of active detached binaries on the logJo-logM diagram and contact binary formation
Orbital angular momentum (OAM, Jo), systemic mass (M) andorbital period (P) distributions of chromospherically active binaries(CAB) and W Ursae Majoris (W UMa) systems were investigated. Thediagrams of and logJo-logM were formed from 119 CAB and 102 WUMa stars. The logJo-logM diagram is found to be mostmeaningful in demonstrating dynamical evolution of binary star orbits. Aslightly curved borderline (contact border) separating the detached andthe contact systems was discovered on the logJo-logM diagram.Since the orbital size (a) and period (P) of binaries are determined bytheir current Jo, M and mass ratio, q, the rates of OAM loss(dlogJo/dt) and mass loss (dlogM/dt) are primary parametersto determine the direction and the speed of the dynamical evolution. Adetached system becomes a contact system if its own dynamical evolutionenables it to pass the contact border on the logJo-logMdiagram. The evolution of q for a mass-losing detached system is unknownunless the mass-loss rate for each component is known. Assuming q isconstant in the first approximation and using the mean decreasing ratesof Jo and M from the kinematical ages of CAB stars, it hasbeen predicted that 11, 23 and 39 per cent of current CAB stars wouldtransform to W UMa systems if their nuclear evolution permits them tolive 2, 4 and 6 Gyr, respectively.
| 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.
| Photoelectric Minima of Selected Eclipsing Binaries and Maxima of Pulsating Stars
Not Available
| The Eclipsing Binary V1061 Cygni: Confronting Stellar Evolution Models for Active and Inactive Solar-Type Stars
We present spectroscopic and photometric observations of the eclipsingsystem V1061 Cyg (P=2.35 days). A third star is visible in the spectrum,and the system is a hierarchical triple. We combine the radialvelocities for the three stars, times of eclipse, and intermediateastrometric data from the Hipparcos mission (abscissa residuals) toestablish the elements of the outer orbit, which is eccentric and has aperiod of 15.8 yr. We determine accurate values for the masses, radii,and effective temperatures of the binary components:MAa=1.282+/-0.015 Msolar,RAa=1.615+/-0.017 Rsolar, andTAaeff=6180+/-100 K for the primary (star Aa), andMAb=0.9315+/-0.0068 Msolar,RAb=0.974+/-0.020 Rsolar, andTAbeff=5300+/-150 K for the secondary (Ab). Themass of the tertiary is determined to be MB=0.925+/-0.036Msolar and its effective temperature isTBeff=5670+/-150 K. Current stellar evolutionmodels agree well with the properties of the primary but show a verylarge discrepancy in the radius of the secondary, in the sense that thepredicted values are ~10% smaller than observed (a ~5 ? effect).In addition, the temperature is cooler than predicted, by some 200 K.These discrepancies are quite remarkable given that the star is only 7%less massive than the Sun, the calibration point of all stellar models.We identify the chromospheric activity as the likely cause of theeffect. Inactive stars agree very well with the models, while activeones such as V1061 Cyg Ab appear systematically too large and too cool.
| Mass loss and orbital period decrease in detached chromospherically active binaries
The secular evolution of the orbital angular momentum (OAM), thesystemic mass (M=M1+M2) and the orbital period of114 chromospherically active binaries (CABs) were investigated afterdetermining the kinematical ages of the subsamples which were setaccording to OAM bins. OAMs, systemic masses and orbital periods wereshown to be decreasing by the kinematical ages. The first-orderdecreasing rates of OAM, systemic mass and orbital period have beendetermined as per systemic OAM, per systemic mass and per orbitalperiod, respectively, from the kinematical ages. The ratio of d logJ/dlogM= 2.68, which were derived from the kinematics of the presentsample, implies that there must be a mechanism which amplifies theangular momentum loss (AML) times in comparison to isotropic AML ofhypothetical isotropic wind from the components. It has been shown thatsimple isotropic mass loss from the surface of a component or bothcomponents would increase the orbital period.
| New Times of Minima of Eclipsing Binary Systems and of Maximum of SXPHE Type Stars
We present 64 photoelectric minima observations of 31 eclipsingbinaries. We also report three new times of maxima of three SXPHE typepulsating stars.
| 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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| Takýmyýldýz: | Zincirli Prenses |
| Sað Açýklýk: | 23h11m10.10s |
| Yükselim: | +53°01'33.0" |
| Görünürdeki Parlaklýk: | 9.053 |
| Uzaklýk: | 75.415 parsek |
| özdevim Sað Açýklýk: | -8 |
| özdevim Yükselim: | -22.6 |
| B-T magnitude: | 9.691 |
| V-T magnitude: | 9.106 |
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