Contents
Images
Upload your image
DSS Images Other Images
Related articles
Contribution to the study of composite spectra: XII. Spectroscopic orbits of eight southern stars
We present the results of a radial-velocity study of eight southern SB1spectroscopic binaries with composite spectra: HD 34318-9, HD 47579-80,HD 70442-3, HD 74946-7, HD 102171-2, HD 120901-2, HD 168701-2, and HD174191-2. The observations were made at Haute-Provence observatory withthe CORAVEL instrument between 1982 and 2006. From the radial-velocitymeasurements of the cool components, we derive the orbital elements ofthose spectroscopic binaries. Using all the available data, we obtain anestimation of the orbital inclination and the angular separation of thetwo components. Finally we discuss the rotation-revolution synchronismof the cool components.
| New CCD Times of Minima of Eclipsing Binary Systems
We present a total of 208 CCD timings for 103 eclipsing binaries.
| Photoelectric Minima of Some Eclipsing Binary Stars
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.
| Updated Elements for Southern Eclipsing Binaries
Analysis of ASAS-3 data for 442 southern eclipsing binaries yielded 131stars with incorrect periods listed in the GCVS catalog
| New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions
In the course of comparing parameters of evolved cool star plus hotmain-sequence star binaries with theoretical isochrones, somediscrepancies are found between implied stellar masses and thespectroscopic binary mass function or the measured angular separation.These are naturally explained if there is a third star in the system.Multiplicity is also required to explain some comparisons of ``cool plushot binary'' IUE and optical spectral energy distribution analysis withmeasured flux ratios, especially Tycho's two-color photometry ofseparate components. Out of a sample of 136 cool-plus-hot binary starsystems under study, measurements are now indicating several systemsconsidered double (HD 5373, 23089, 26673, 29094, 49126, 71129, 149379,179002, 187299), and probably a few others (including HD 136415), tohave at least three stellar components. Several other cases of suspectedtriple systems are confirmed. For comparison, there are eight knowntriples included in the project. In all, about 25% of the systemscontain three or more components within a few arcseconds. Estimatedseparations are provided, which may be of use when not known frominterferometry. In general, the triple systems have onepost-main-sequence component and two upper main-sequence components,usually revolving around each other. One new triple system, HD 149379,has as its middle component an F giant in the brief first crossing ofthe Hertzsprung gap.
| 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
| Reprocessing the Hipparcos Intermediate Astrometric Data of spectroscopic binaries. II. Systems with a giant component
By reanalyzing the Hipparcos Intermediate Astrometric Data of a largesample of spectroscopic binaries containing a giant, we obtain a sampleof 29 systems fulfilling a carefully derived set of constraints andhence for which we can derive an accurate orbital solution. Of these,one is a double-lined spectroscopic binary and six were not listed inthe DMSA/O section of the catalogue. Using our solutions, we derive themasses of the components in these systems and statistically analyzethem. We also briefly discuss each system individually.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997) and on data collected with theSimbad database.
| Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components.
A sample of 135 stars with composite spectra has been observed in thenear-UV spectral region with the Aurélie spectrograph at theObservatoire de Haute-Provence. Using the spectral classifications ofthe cool components previously determined with near infrared spectra, weobtained reliable spectral types of the hot components of the samplesystems. The hot components were isolated by the subtraction methodusing MK standards as surrogates of the cool components. We also derivedthe visual magnitude differences between the components usingWillstrop's normalized stellar flux ratios. We propose a photometricmodel for each of these systems on the basis of our spectroscopic dataand the Hipparcos data. We bring to light a discrepancy for the Gsupergiant primaries between the visual absolute magnitudes deduced fromHipparcos parallaxes and those tabulated by Schmidt-Kaler for the GIbstars: we propose a scale of Mv-values for these stars incomposite systems. By way of statistics, about 75% of the hot componentsare dwarf or subgiant stars, and 25% should be giants. The distributionin spectral types is as follows: 41% of B-type components, 57% of typeA, and 2% of type F; 68% of the hot components have a spectral type inthe range B7 to A2. The distribution of the ΔMv-valuesshows a maximum near 0.75 mag.
| The Evolution of Cool Algols
We apply a model of dynamo-driven mass loss, magnetic braking, and tidalfriction to the evolution of stars with cool convective envelopes; inparticular, we apply it to binary stars where the combination ofmagnetic braking and tidal friction can cause angular momentum loss fromthe orbit. For the present we consider the simplification that only onecomponent of a binary is subject to these nonconservative effects, butwe emphasize the need in some circumstances to permit such effects inboth components.The model is applied to examples of (1) the Sun, (2) BYDra binaries, (3) Am binaries, (4) RS CVn binaries, (5) Algols, and (6)post-Algols. A number of problems regarding some of these systems appearto find a natural explanation in our model. There are indications fromother systems that some coefficients in our model may vary by a factorof 2 or so from system to system; this may be a result of the chaoticnature of dynamo activity.
| The tidal effects on the lithium abundance of binary systems with giant component
We analyse the behavior of lithium abundance as a function of effectivetemperature, projected rotational velocity, orbital period andeccentricity for a sample of 68 binary systems with giant component andorbital period ranging from about 10 to 6400 days. For these binarysystems the Li abundances show a gradual decrease with temperature,paralleling the well established result for single giants. We have alsoobserved a dependence of lithium content on rotation. Binary systemswith moderate to high rotation present also moderate to high Li content.This study shows also that synchronized binary systems with giantcomponent seem to retain more of their original lithium than theunsynchronized systems. For orbital periods lower than 100 to 250 days,typically the period of synchronization for this kind of binary systems,lithium depleted stars seems to be unusual. The suggestion is made thatthere is an ``inhibited zone" in which synchronized binary systems withgiant component having lithium abundance lower than a threshold levelshould be unusual. Based on observations collected at ESO, La Silla.
| The Origin of Cyclic Period Changes in Close Binaries: The Case of the Algol Binary WW Cygni
Year- to decade-long cyclic orbital period changes have been observed inseveral classes of close binary systems, including Algol, W UrsaeMajoris, and RS Canum Venaticorum systems and the cataclysmic variables.The origin of these changes is unknown, but mass loss, apsidal motion,magnetic activity, and the presence of a third body have all beenproposed. In this paper, we use new CCD observations and thecentury-long historical record of the times of primary eclipse for WWCygni to explore the cause of these period changes. WW Cyg is an Algolbinary whose orbital period undergoes a 56 yr cyclic variation with anamplitude of ~0.02 days. We consider and reject the hypotheses of masstransfer, mass loss, apsidal motion, and the gravitational influence ofan unseen companion as the cause for these changes. A model proposed byApplegate, which invokes changes in the gravitational quadrupole momentof the convective and rotating secondary star, is the most likelyexplanation of this star's orbital period changes. This finding is basedon an examination of WW Cyg's residual O-C curve and an analysis of theperiod changes seen in 66 other Algols. Variations in the gravitationalquadrupole moment are also considered to be the most likely explanationfor the cyclic period changes observed in several different types ofbinary systems.
| Dynamical Stability of Triple Stars
The dynamical stability of 38 observed hierarchical triple stars withknown orbital elements of the internal and external binary subsystemsand component masses is considered. Four different criteria of dynamicalstability are used. The observed stability parameters and their criticalvalues are calculated by taking into account errors in the orbitalelements and component masses. Most triple systems are stable. Accordingto some criteria, several triple stars (ADS440, xi Tau, lambda Tau,ADS3358, VV Ori, ADS10157, HZ Her, Gliese 795, ADS15971, and ADS16138)may be dynamically unstable. This result is probably associated withunreliability of the empirical stability criteria and/or with errors inthe observed quantities.
| Speckle Interferometry of New and Problem HIPPARCOS Binaries
The ESA Hipparcos satellite made measurements of over 12,000 doublestars and discovered 3406 new systems. In addition to these, 4706entries in the Hipparcos Catalogue correspond to double star solutionsthat did not provide the classical parameters of separation and positionangle (rho,theta) but were the so-called problem stars, flagged ``G,''``O,'' ``V,'' or ``X'' (field H59 of the main catalog). An additionalsubset of 6981 entries were treated as single objects but classified byHipparcos as ``suspected nonsingle'' (flag ``S'' in field H61), thusyielding a total of 11,687 ``problem stars.'' Of the many ground-basedtechniques for the study of double stars, probably the one with thegreatest potential for exploration of these new and problem Hipparcosbinaries is speckle interferometry. Results are presented from aninspection of 848 new and problem Hipparcos binaries, using botharchival and new speckle observations obtained with the USNO and CHARAspeckle cameras.
| Spectral classifications in the near infrared of stars with composite spectra. III. Study of a sample of 137 objects with the Aurelie spectrograph
We provide spectral classifications for a sample of 137 stars mentionedas having composite spectra. The classifications were carried out on 33Angstroms /mm spectra in the region 8370 - 8870 Angstroms. Of these 137objects, 115 correspond in the infrared to cool stars (G, K or M) ofluminosity classes III, II and I; for 22 stars, we find only hot spectraof types B, A, F or Am, so that they do not fulfil our definition ofcomposite spectra. We detect four new Am stars, and one Am star (HD70826) turns out to be a composite spectrum object. As in Paper II, thecool components of composite spectra show a strong concentration in thevicinity of G8III. Based upon observations carried out at Observatoirede Haute-Provence (OHP).
| Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample
We have obtained or retrieved IUE spectra for over 100 middle- andlate-type giant and supergiant stars whose spectra indicate the presenceof a hot component earlier than type F2. The hot companions areclassified accurately by temperature class from their far-UV spectra.The interstellar extinction of each system and the relative luminositiesof the components are derived from analysis of the UV and opticalfluxes, using a grid of UV intrinsic colors for hot dwarfs. We find thatthere is fair agreement in general between current UV spectralclassification and ground-based hot component types, in spite of thedifficulties of assigning the latter. There are a few cases in which thecool component optical classifications disagree considerably with thetemperature classes inferred from our analysis of UV and opticalphotometry. The extinction parameter agrees moderately well with otherdeterminations of B-V color excess. Many systems are worthy of furtherstudy especially to establish their spectroscopic orbits. Further workis planned to estimate luminosities of the cool components from the dataherein; in many cases, these luminosities' accuracies should becomparable to or exceed those of the Hipparcos parallaxes.
| MSC - a catalogue of physical multiple stars
The MSC catalogue contains data on 612 physical multiple stars ofmultiplicity 3 to 7 which are hierarchical with few exceptions. Orbitalperiods, angular separations and mass ratios are estimated for eachsub-system. Orbital elements are given when available. The catalogue canbe accessed through CDS (Strasbourg). Half of the systems are within 100pc from the Sun. The comparison of the periods of close and widesub-systems reveals that there is no preferred period ratio and allpossible combinations of periods are found. The distribution of thelogarithms of short periods is bimodal, probably due to observationalselection. In 82\% of triple stars the close sub-system is related tothe primary of a wide pair. However, the analysis of mass ratiodistribution gives some support to the idea that component masses areindependently selected from the Salpeter mass function. Orbits of wideand close sub-systems are not always coplanar, although thecorresponding orbital angular momentum vectors do show a weak tendencyof alignment. Some observational programs based on the MSC aresuggested. Tables 2 and 3 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Spectral classifications in the near infrared of stars with composite spectra. II. Study of a sample of 180 stars
A sample of 180 supposedly composite-spectrum stars has been studied onthe basis of spectra obtained in the near infrared (8370-8780 Angstroms)at a dispersion of 33 Anstroms/mm. The objective was to study the coolercomponents of the systems. Of our sample, 120 are true compositespectra, 35 are hot spectra of types B, F and 25 are Am stars. We find astrong concentration of the cooler components of the composite spectraaround G8III. In view of the difficulty of classifying compositespectra, because of the super position of an early type dwarf and a latetype giant or supergiant spectrum, we have made several tests to controlthe classification based upon the infrared region. Since all tests gavepositive results, we conclude that our classifications can be consideredas being both reliable and homogeneous. Table \ref{tab1} is alsoavailable electronically at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstracts.html} Based upon observationscarried out at Observatoire de Haute-Provence (CNRS).
| CCD Photometry of Five Neglected Eclipsing Binary Stars
Differential V-magnitude CCD photometric data are presented for fiveneglected eclipsing binary stars with shallow eclipses. An improvedperiod is derived for SV Equ, past O-C trends are confirmed for AN Andand DL Vir, and an unexpectedly large O-C values are found for BW DELnad CS Lac.
| 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.
| The effect of eccentricity on three-body orbital stability criteria and its importance for triple star systems
Previous investigations of prograde three-body hierarchical systems witheccentric orbits do not give consistent results. The problem isre-examined for mass configurations particularly important in triplestar systems. It is found that, for systems with binaries moving oncircular orbits, the regions of stability expand slightly in size forlarge mass ratios and contract slightly for small mass ratios as theeccentricity of the outer mass is increased. Comparison of the systemswith their retrograde counterparts indicates that the retrograde are themore stable systems. Increasing the eccentricity of the binary canreduce stability significantly for small outer-body eccentricities andincrease it for large values, but makes little difference forintermediate eccentricities. The analytical c^2 H criterion mirrors thesame general behaviour in the prograde cases, but is not found to be agood quantitative indicator of orbital stability when eccentric orbitsare present, unlike the situation found by Donnison & Mikulskis whenall the orbits are circular. Actual triple star systems with visualbinary components (visual triples) are compared with the criticalcondition for stability for both prograde and retrograde configurations,and are found to be within the stable region regardless of whether theyare prograde or retrograde. It is also found that retrogradeconfigurations tend to be the more stable when the binary eccentricityis small, while for systems with both large binary and outer-bodyeccentricities the prograde configurations are the more stable. Triplesystems with spectroscopic binaries (spectroscopic-visual triples) areshown to lie well within the limits of stability for prograde andretrograde configurations.
| Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
| Statistical Analysis of a Sample of Spectroscopic Binaries Containing Late Type Giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&A...271..125B&db_key=AST
| Eclipsing binaries in multiple-star systems
Some 80 eclipsing binaries that are components of multiple-star systemsare considered. Orbits for the third components of these systems aredetermined for only a relatively small number of cases, and all of thesethat have been published to date are presented. Triple-star systems areby far the most common of these, but one system in five is a quadrupleor higher-order system. Eclipsing binaries in compact star clusters suchas SZ Camelopardalis and the two binaries in Trapezium, BM Ori, and V1016 Ori are also considered. The physical and orbital properties of themultiple star systems are discussed in detail in cases where the dataare fairly complete. In triple-star systems with eclipsing binaries theratio of P2/P1 ranges from less than 10 (for Lambda Tauri) to more than10 exp 7 in some cases. The questions of coplanarity of orbits and themembership of components in multiple-star systems are also examined.
| A microwave survey of selected Algol systems with the VLA
The results are presented of a limited microwave survey of Algol-typesystems carried out with the VLA. Seven of the fourteen observed systemswere detected. The average radio luminosity at 6 cm L6 turnedout to be 1.58 x 10 exp 16 erg/s/Hz, and thus comparable to the medianradio luminosity for the larger sample of RS CVn reported by Morris andMutel (1988). The high values of the brightness temperature, obtained byassuming a characteristic dimension for the emission region, suggest anonthermal origin for the radio emission. The observations areconsistent with gyrosynchrotron emission from mildly relativisticelectrons interacting with the magnetic field of the active component.This makes Algol-type systems comparable to the RS CVn class of binaryradio sources.
| Rotation statistics of Algol-type binaries and results on RY Geminorum, RW Monocerotis, and RW Tauri
Rotation rates and other parameters are estimated from light curves ofthree Algol-type binaries, and rotation statistics based on bothspectral line broadening and light curves are collected for 36 Algolsystems. The statistics suggest that a subset of Algols have primarystars which rotate at the centrifugal limit and that many Algols havesufficient continual mass transfer to maintain nonsynchronous rotation.A formal procedure for estimating the critical rotation rate(centrifugal limit) is described. It is found that RY Gem rotates about14 times faster than synchronously, but not close to its centrifugallimit of about 24 times. For RW Mon, the rotation is about five timessynchronous. For RW Tau it was not possible to estimate the rotationfrom the light curves, but consistency with a published result from linebroadening is found.
| Statistical Study of the Rotation of ALGOLS
Not Available
| A Study of the DM and SD Type Eclipsing Variables by Means of the Cluster Analysis Technique
Not Available
| A Catalogue of Classical Evolved Algol-Type Binary Candidate Stars
Not Available
| Synchronization in eclipsing binary stars
Improving previous studies, the synchronism between rotation andrevolution has been rediscussed for close binaries by inspection of thepublished rotational velocities of about 140 eclipsing (and ellipsoidal)binary components. Basically, it has been found that almost all membersof detached systems are synchronized up to fractional radii of rapproximately 0.15, whereas, below this r-value, both synchronized andasynchronized rotators are encountered with roughly comparable frequencyup to r approximately equal to or less than 0.10. The corresponding highfraction of synchronized stars with r less than 0.15 appears to beclearly incompatible with current theoretical predictions (e.g., Zahn,1977) on synchronization time scales.
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Virgo |
| Right ascension: | 13h52m38.81s |
| Declination: | -18°42'32.5" |
| Apparent magnitude: | 6.995 |
| Distance: | 280.899 parsecs |
| Proper motion RA: | -49.3 |
| Proper motion Dec: | 4.2 |
| B-T magnitude: | 7.75 |
| V-T magnitude: | 7.058 |
Catalogs and designations:
|
