HS Hydrae about to turn off its eclipses
Aims: We aim to perform the first long-term analysis of thesystem HS Hya. Methods: We performed an analysis of the long-termevolution of the light curves of the detached eclipsing system HS Hya.Collecting all available photometric data since its discovery, the lightcurves were analyzed with a special focus on the evolution of system'sinclination. Results: We find that the system undergoes a rapidchange of inclination. Since its discovery until today the system'sinclination changed by more than 15°. The shape of the light curvechanges, and now the eclipses are almost undetectable. The third distantcomponent of the system is causing the precession of the close orbit,and the nodal period is about 631 yr. Conclusions: New preciseobservations are desperately needed, preferably this year, because theamplitude of variations is decreasing rapidly every year. We know only10 such systems on the whole sky at present.
|
Random forest automated supervised classification of Hipparcos periodic variable stars
We present an evaluation of the performance of an automatedclassification of the Hipparcos periodic variable stars into 26 types.The sub-sample with the most reliable variability types available in theliterature is used to train supervised algorithms to characterize thetype dependencies on a number of attributes. The most useful attributesevaluated with the random forest methodology include, in decreasingorder of importance, the period, the amplitude, the V-I colour index,the absolute magnitude, the residual around the folded light-curvemodel, the magnitude distribution skewness and the amplitude of thesecond harmonic of the Fourier series model relative to that of thefundamental frequency. Random forests and a multi-stage scheme involvingBayesian network and Gaussian mixture methods lead to statisticallyequivalent results. In standard 10-fold cross-validation (CV)experiments, the rate of correct classification is between 90 and 100per cent, depending on the variability type. The main mis-classificationcases, up to a rate of about 10 per cent, arise due to confusion betweenSPB and ACV blue variables and between eclipsing binaries, ellipsoidalvariables and other variability types. Our training set and thepredicted types for the other Hipparcos periodic stars are availableonline.
|
Masses and luminosities of O- and B-type stars and red supergiants
Massive stars are of interest as progenitors of supernovae, i.e.neutron stars and black holes, which can be sources of gravitationalwaves. Recent population synthesis models can predict neutron star andgravitational wave observations but deal with a fixed supernova rate oran assumed initial mass function for the population of massive stars. Here we investigate those massive stars, which are supernovaprogenitors, i.e. with O- and early B-type stars, and also allsupergiants within 3 kpc. We restrict our sample to those massive starsdetected both in 2MASS and observed by Hipparcos, i.e. only those starswith parallax and precise photometry. To determine the luminositieswe calculated the extinctions from published multi-colour photometry,spectral types, luminosity class, all corrected for multiplicity andrecently revised Hipparcos distances. We use luminosities andtemperatures to estimate the masses and ages of these stars usingdifferent models from different authors. Having estimated theluminosities of all our stars within 3 kpc, in particular for all O- andearly B-type stars, we have determined the median and mean luminositiesfor all spectral types for luminosity classes I, III, and V. Ourluminosity values for supergiants deviate from earlier results: Previouswork generally overestimates distances and luminosities compared to ourdata, this is likely due to Hipparcos parallaxes (generally moreaccurate and larger than previous ground-based data) and the fact thatmany massive stars have recently been resolved into multiples of lowermasses and luminosities. From luminosities and effective temperatureswe derived masses and ages using mass tracks and isochrones fromdifferent authors. From masses and ages we estimated lifetimes andderived a lower limit for the supernova rate of ?20 events/Myraveraged over the next 10 Myr within 600 pc from the sun. These data arethen used to search for areas in the sky with higher likelihood for asupernova or gravitational wave event (like OB associations).
|
SV Gem beobachtet.
Not Available
|
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.
|
Beobachtungsaufruf zu SV Geminorum.
Not Available
|
Aus der Sektion Bedeckungsveranderliche.
Not Available
|
SB9: The ninth catalogue of spectroscopic binary orbits
The Ninth Catalogue of Spectroscopic Binary Orbits(http://sb9.astro.ulb.ac.be) continues the series of compilations ofspectroscopic orbits carried out over the past 35 years by Batten andcollaborators. As of 2004 May 1st, the new Catalogue holds orbits for2386 systems. Some essential differences between this catalogue and itspredecessors are outlined and three straightforward applications arepresented: (1) completeness assessment: period distribution of SB1s andSB2s; (2) shortest periods across the H-R diagram; (3)period-eccentricity relation.
|
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
|
On the detectability of long period perturbations in close hierarchical triple stellar systems
We study the possibility of the detection of the low amplitude long (P')period perturbative effect of a distant third companion on the motion ofa close binary. We give a new, more accurate analytical formula for thiskind of perturbation affecting the moments of the times of minima ineclipsing binaries. The accuracy of this formula is tested by numericalintegrations carried out for several initial configurations. We alsodescribe a numerical method based on a non-linear Levenberg-Marquardtalgorithm which makes it possible to separate this dynamical effect fromthe pure geometrical light-time effect in the eclipsing O-C diagram. Thecapabilities of this new method are demonstrated by the analysis ofnumerically simulated O-Cs for test systems having physical parametersvery similar to Algol and IU Aur.The results show that the above mentioned effect would be detectable inthese systems nowadays, observing almost each minima events in a 1-2year-long interval.
|
149 Bedeckungssterne der BAV-Programme. Eine Analyse der Beobachtungstatigkeit seit den Angangen.
Not Available
|
Das Brunner Punktesystem.
Not Available
|
A Study of the Non-Eclipsing Binary SV Geminorum
The variation in the eclipse depths of SV Gem is followed for over 100years on photographic plates from the Harvard College Observatory.Eclipses of over 1.5 mag became barely detectable within about 10 yearsand have since completely disappeared
|
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.
|
An Updated List of Eclipsing Binaries Showing Apsidal Motion
Not Available
|
Absolute parameters of stars in semidetached eclipsing binary systems
A number of questions concerning the absolute parameters of stars insemidetached binary systems are addressed. Consideration is given to:similarities between Algol-type binaries and unevolved detached binarieswith respect to the mass-luminosity law; and the single-line classicalAlgol candidates with known mass functions and photometric solutions formass ratio. It is shown that the validity of the mass luminosity-lawcannot be verified for individual Algol-type binaries though it doeshold well on average; and (2), the existence of a definite class ofsd-binaries not containing a proportion of significantly undersize typesis apparent. The conclusions are found to be in general agreement withthe observations of Hall and Neff (1979).
|
A Catalogue of Classical Evolved Algol-Type Binary Candidate Stars
Not Available
|
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).
|
A catalogue of parameters for eclipsing binaries
Not Available
|
A comparison of the orbital inclinations of the spatially close spectroscopic double stars
The reported investigation takes into account 888 spectroscopicbinaries. It was possible to obtain 120 groups whose elements arespatially close according to the given definition. These 120 groupscontain 313 spectroscopic binaries. 136 of these binaries are 2-spectrumsystems, 177 are 1-spectrum systems, and 62 are eclipsing binaries. Thenumber of systems with known luminosity class is 54. The spectraldistribution of the 313 systems is discussed. The orbital inclinationsand other parameters are presented in a table.
|
Seventh catalogue of the orbital elements of spectroscopic binary systems.
Not Available
|
Strömgren four-colour observations of Northern Hemisphere binary systems
Not Available
|
Spectroscopic binaries with circular orbits.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971AJ.....76..544L&db_key=AST
|
Spectroscopic Binaries and Collapsed Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969ApJ...156.1013T&db_key=AST
|
Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969PASP...81..105H&db_key=AST
|
The stellar distribution in the galactic anticenter.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1967AJ.....72.1199M&db_key=AST
|
Minima and periods of eclipsing stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1959AJ.....64..258W&db_key=AST
|
Uber die Massen von Bedeckungsveranderlichen mit bekannter Radialgeschwindigkeit nur des Hauptsterns.
Not Available
|
Die Bedeckungsveraenderlichen
Not Available
|
