|Observed Orbital Eccentricities|
For 391 spectroscopic and visual binaries with known orbital elementsand having B0-F0 IV or V primaries, we collected the derivedeccentricities. As has been found by others, those binaries with periodsof a few days have been circularized. However, those with periods up toabout 1000 or more days show reduced eccentricities that asymptoticallyapproach a mean value of 0.5 for the longest periods. For those binarieswith periods greater than 1000 days their distribution of eccentricitiesis flat from 0 to nearly 1, indicating that in the formation of binariesthere is no preferential eccentricity. The binaries with intermediateperiods (10-100 days) lack highly eccentric orbits.
|Tidal Effects in Binaries of Various Periods|
We found in the published literature the rotational velocities for 162B0-B9.5, 152 A0-A5, and 86 A6-F0 stars, all of luminosity classes V orIV, that are in spectroscopic or visual binaries with known orbitalelements. The data show that stars in binaries with periods of less thanabout 4 days have synchronized rotational and orbital motions. Stars inbinaries with periods of more than about 500 days have the samerotational velocities as single stars. However, the primaries inbinaries with periods of between 4 and 500 days have substantiallysmaller rotational velocities than single stars, implying that they havelost one-third to two-thirds of their angular momentum, presumablybecause of tidal interactions. The angular momentum losses increase withdecreasing binary separations or periods and increase with increasingage or decreasing mass.
|On the Variability of A3-F0 Luminosity Class III-V Stars|
I investigate the Hipparcos Satellite photometry of A3-F0 stars ofluminosity classes III-V to learn about their variability and identify afew stars for which further study is desirable.
|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|
|The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJS...99..135A&db_key=AST
|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 position corrections of 1400 stars observed with PA II in San Juan.|
|Improved Mean Positions and Proper Motions for the 995 FK4 Sup Stars not Included in the FK5 Extension|
|Speckle observations of visual and spectroscopic binaries. V.|
|Speckle observations of visual and spectroscopic binaries. IV|
This is the fourth paper of this series giving results of speckleobservations for 22 visual and 161 spectroscopic binaries. Theobservation was carried out by using the 212 cm telescope of San PedroMartir Observatory in Mexico on 7 nights from July 20 to July 26, 1991.We obtained fringes in power spectra of 19 visual and 11 spectroscopicbinaries (6 newly resolved ones) with angular separation larger than0.06 arcsec. We introduced a new ICCD TV camera in this observation, andwere able to achieve the diffraction-limit resolution of the 212 cmtelescope.
|Armagh Observatory in 1985-86|
|The Sirius supercluster|
Photometric data on the chemical composition of 927 A stars in the UrsaMajor stream, called the Sirius supercluster, were used to estimate theage and place of formation of the objects. The stars studied are in thesolar neighborhood and have been observed to be co-moving in a velocityellipsoid with a (U, V) velocity of 10.3 km/sec and concentrated in aspatial volume less than 10 pc across. The Stromgren and Geneva systemphotometric data show that the supercluster is homogeneous in chemicalcontent, although the value of the forbidden Fe/H ratio could not beprecisely determined. The supercluster age is projected to be from260-620 Myr, with the origin having been in the Carina spiral arm of theGalaxy.
|Metallicism among A and F giant stars|
132 stars considered as A and F giants have been studied for theirproperties in the Geneva photometric system. It is shown that thissystem to derive the temperature, absolute magnitude and Fe/H value forstars in this part of the HR diagram. 36 percent of the stars of oursample exhibit an enhanced value Delta m2 that can be interpreted interms of Fe/H. The red limit of stars having an enhanced Fe/H value is0.225 in B2-V1 or 6500 K in Teff. This corresponds to the limit definedby Vauclair and Vauclair (1982) where the diffusion timescale is equalto the stellar lifetime and permits the assumption that the diffusion isthe process responsible for the metallicism observed in the A and Fgiants.
|The 67th Name-List of Variable Stars|
|A Note about the Comparison Between the Old and New Slettebak Systems of Axial Rotational Velocities|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984RMxAA...9....9G&db_key=AST
|Preliminary Orbital Elements of HD 184035|
|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.
|Variability of the emission-line spectra and optical continua of Seyfert galaxies. I|
H-beta and O III forbidden line 4959,5007 A line strengths obtained fromnew observations of 27 broad line-emitting galaxies and six narrowline-emitting galaxies are compared with earlier measurements. It isfound that about 80% of broad line-emitting galaxies show significantchanges in their optical spectra, on time scales of less than about fiveyears. An analysis of changes in O II forbidden line/H-beta ratio for 24broad line-emitting galaxies shows that (1) changes in the H-beta fluxare correlated with changes in the optical continuum, providing evidencefor energy input into the line-emitting region by photoionization, and(2) in a number of galaxies, the structure of the broad emission linesin complex, with detailed line structure changes on time scales shorterthan about two months.
|A search for X-ray binary stars in their quiescent phase|
Fourteen early-type stars representative of systems which may beharboring a neutron star companion and are thus potential progenitors ofmassive X-ray binaries have been examined for X-ray emission with theHEAO A-1 experiment. Limits on the 0.5-20 keV luminosity for theseobjects lie in the range 10 to the 31-33 erg/sec. In several cases, thehypothesis of a collapsed companion, in combination with the X-raylimit, places a serious constraint on the mass-loss rate of the primarystar. In one instance, an X-ray source was discovered coincident with acandidate star, although the luminosity of 5 x 10 to the 31 isconsistent with that expected from a single star of the same spectraltype. The prospects for directly observing the quiescent phase of abinary X-ray source with the Einstein Observatory are discussed in thecontext of these results.
|Detection of low eccentricity orbits - an analysis of nine massive spectroscopic binaries|
The elements of nine single-lined, short-period, massive spectroscopicbinaries are analyzed for significant orbital eccentricity. The Fouriertransform formalism for computation of orbits is used to derive anestimator of significance for the observed eccentricity. Of the ninesystems investigated, five are either probably or possibly in eccentricorbits.
|Seventh catalogue of the orbital elements of spectroscopic binary systems.|
|Spectral classification from the ultraviolet line features of S2/68 spectra. III - Early A-type stars|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978A&AS...33...15C&db_key=AST
|Synchronization in binaries and age.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976ApJ...203..680L&db_key=AST
|Rotational velocities and spectral types for a sample of binary systems.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975A&AS...19...91L&db_key=AST
|Mitteilungen uber Veraenderliche der Bamberger Liste.|
|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
|Spectroscopic binaries with circular orbits.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971AJ.....76..544L&db_key=AST