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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.
| Eclipsing binaries with candidate CP stars. I. Parameters of the systems HD 143654, HD 184035 and HD 185257.
Lightcurves of three eclipsing binaries (HD 143654 = TV Nor, HD 184035 =HR 7422 and HD 185257 = HR 7464) in seven colours are analyzed and theirphotometric elements are given. Published radial velocities of two ofthem allow some constraints to be put on the masses of the components,while new radial velocities allow us to estimate the mass and absoluteradius of each component of the system TV Nor. There seems to be no Apstar in this system, in spite of its EuCrSr classification in theMichigan catalogue. The position of each component of TV Nor in the HRdiagram is in excellent agreement with stellar evolution models havingZ=0.020 and an age t=2.51x10^8^years. There is an Am star in the systemHD 185257, but no CP star in the system HD 184035 in spite of its sharplines. The physical parameters of these two binaries could bedetermined, but less accurately and in a less fundamental way than thoseof TV Nor. They match theoretical isochrones and evolutionary tracks ina satisfactory way for HD 185257, but the measured mass function of HD184035 seems slightly too small compared with the expected theoreticalmasses. More data, both photometric and spectroscopic, would be useful,especially for the last two systems.
| A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars
Among the 9110 stars in The Bright Star Catalogue, there are 225eclipsing or ellipsoidal variables. A search has been made for these incatalogues of spectroscopic binaries, visual double or multiple stars,speckle interferometry, occulation binaries, and galatic clusters. Themajority of the photometric binaries are also members of groups ofhigher multiplicity. The variables are in systems ranging from one to 91stars, five on the average. 199 are either spectroscopic binaries (SB)or stars with variable radial velocity, with orbital periods known for160. Photometric periods are lacking for 48 while SB periods areavailable for 23 of these. Observers with photoelectric equipment areencouraged to plan observations to test if the SB periods are consistentwith photometric data. Observers are likewise encouraged to examinethose stars for which the photometric and SB periods appear to beinconsistent. Parallaxes are available for 86 of the stars, 41 of themindicating distances nearer than 50 parsecs.
| Eclipse Monitoring of Eccentric Binary Systems
Not Available
| The 67th Name-List of Variable Stars
Not Available
| Detached eclipsing binaries with very unequal members - HR 7464
Waelkens and Rufener's (1983) photoelectric lightcurve (as yetunexplored) of the newly discovered eclipsing binary HR 7464 has beenanalyzed. The photometric solution presented here reveals that thisbinary is an A5m + G main sequence detached system, which isparticularly remarkable for the great dissimilarity between its members.The frequency of detached eclipsing pairs with very unequal members(i.e., with low mass ratio) is then discussed; some bimodality in theinnate mass ratio distribution of close binaries is inferred.
| 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).
| Light curves of four southern bright hitherto unknown eclipsing binaries
Photometric light curves are presented for four bright southerneclipsing binaries, that were not yet known as variable stars or forwhich the variability was not yet understood. HR 7464 is a probable Amstar in an eclipsing binary; the known single-lined spectroscopic binaryHR 7422 shows two similar eclipses, so spectra with a high resolutionshould reveal the secondary too; both HR 6621 and HR 5034 are early-typeclose binaries for which there is evidence for variations of the orbitalperiod. In particular, HR 5034 is an evolved B3 star with an orbitalperiod of only 1.278 day, so it could be near a contact configuration.
| Lists of photometric AM candidates
The Geneva photometric m parameter (Nicolet and Cramer, 1982) is used inorder to select Am photometric candidates from the Rufener (1981)catalogue. Two lists are given, the first containing field stars and thesecond cluster stars. According to the photometric criteria thediffusion process probably responsible for the Am phenomenon takes placerather quickly as Am candidates are present in young clusters. It isconfirmed that the phenomenon is enhanced by low rotational velocity andhigh metallicity. The age seems to slightly affect the Am phenomenon.
| List of 333 variable, microvariable or suspected variable stars detected in the Geneva photometry
A list is presented of 333 stars, excluded from the GCVS and itssupplements, whose probability of variability ranges from high tocertain. The standard deviations observed in the V magnitude togetherwith the known spectral types, however, only allow speculation as to thetype of variable in question pending supplementary observations whichreveal the individual characteristics of these stars.
| Properties of AM stars in the Geneva photometric system
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&A....92..289H&db_key=AST
| Bright southern stars of astrophysical interest
The paper lists a number of bright peculiar stars in the SouthernHemisphere discovered on 20-A/mm spectrograms. Recent information isalso given for a few known peculiar objects. The lists include: oneLambda Boo star, 4 Hg and other Bp stars, 7 Am stars, 17 shell oremission-line stars, and 37 double-lined spectroscopic binaries, amongwhich are two triple-lined, four composite, eight variable or eclipsing,and three peculiar shell and/or emission-line systems.
| Four-colour and H BET photometry of some bright southern stars- II.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972MNRAS.160..155S&db_key=AST
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Osservazione e dati astrometrici
| Costellazione: | Sagittario |
| Ascensione retta: | 19h39m55.70s |
| Declinazione: | -39°26'00.0" |
| Magnitudine apparente: | 6.61 |
| Distanza: | 84.459 parsec |
| Moto proprio RA: | 46 |
| Moto proprio Dec: | -48 |
| B-T magnitude: | 6.908 |
| V-T magnitude: | 6.649 |
Cataloghi e designazioni:
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