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# HD 189178

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 Evolution of interacting binaries with a B type primary at birthWe revisited the analytical expression for the mass ratio distributionfor non-evolved binaries with a B type primary. Selection effectsgoverning the observations were taken into account in order to comparetheory with observations. Theory was optimized so as to fit best withthe observed q-distribution of SB1s and SB2s. The accuracy of thistheoretical mass ratio distribution function is severely hindered by theuncertainties on the observations. We present a library of evolutionarycomputations for binaries with a B type primary at birth. Some liberalcomputations including loss of mass and angular momentum during binaryevolution are added to an extensive grid of conservative calculations.Our computations are compared statistically to the observeddistributions of orbital periods and mass ratios of Algols. ConservativeRoche Lobe Over Flow (RLOF) reproduces the observed distribution oforbital periods but fails to explain the observed mass ratios in therange q in [0.4-1]. In order to obtain a better fit the binaries have tolose a significant amount of matter, without losing much angularmomentum. Observed Orbital EccentricitiesFor 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 PeriodsWe 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. Rotational Velocities of B StarsWe measured the projected rotational velocities of 1092 northern B starslisted in the Bright Star Catalogue (BSC) and calibrated them againstthe 1975 Slettebak et al. system. We found that the published values ofB dwarfs in the BSC average 27% higher than those standards. Only 0.3%of the stars have rotational velocities in excess of two-thirds of thebreakup velocities, and the mean velocity is only 25% of breakup,implying that impending breakup is not a significant factor in reducingrotational velocities. For the B8-B9.5 III-V stars the bimodaldistribution in V can be explained by a set of slowly rotating Ap starsand a set of rapidly rotating normal stars. For the B0-B5 III-V starsthat include very few peculiar stars, the distributions in V are notbimodal. Are the low rotational velocities of B stars due to theoccurrence of frequent low-mass companions, planets, or disks? Therotational velocities of giants originating from late B dwarfs areconsistent with their conservation of angular momentum in shells.However, we are puzzled by why the giants that originate from the earlyB dwarfs, despite having 3 times greater radii, have nearly the samerotational velocities. We find that all B-type primaries in binarieswith periods less than 2.4 days have synchronized rotational and orbitalmotions; those with periods between 2.4 and 5.0 days are rotating withina factor 2 of synchronization or are nearly synchronized.'' Thecorresponding period ranges for A-type stars are 4.9 and 10.5 days, ortwice as large. We found that the rotational velocities of the primariesare synchronized earlier than their orbits are circularized. The maximumorbital period for circularized B binaries is 1.5 days and for Abinaries is 2.5 days. For stars of various ages from 107.5 to1010.2 yr the maximum circularized periods are a smoothexponential function of age. Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statisticsThe Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521 Eclipsing Binaries as Astrophysical Laboratories: Internal Structure, Core Convection, and Evolution of the B-Star Components of V380 CygniNew photometric solutions have been carried out on the importanteccentric eclipsing system V380 Cygni (B1.5 II-III+B2 V) from UBVdifferential photoelectric photometry obtained by us. The photometricelements obtained from the analysis of the light curves have beencombined with the spectroscopic solution recently published by Popper& Guinan and have led to the physical properties of the systemcomponents. The effective temperature of the stars has been determinedby fitting IUE UV spectrophotometry to Kurucz model atmospheres andcompared with other determinations from broadband and intermediate-bandstandard photometry. The values of mass, absolute radius, and effectivetemperature for the primary and secondary stars are 11.1+/-0.5Msolar, 14.7+/-0.2 Rsolar, 21,350+/-400 K, and6.95+/-0.25 Msolar, 3.74+/-0.07 Rsolar,20,500+/-500 K, respectively. In addition, a redetermination of thesystem's apsidal motion rate has been done from the analysis of 12eclipse timings obtained from 1923 to 1995. The apsidal motion studyyields the internal mass distribution of the more luminous component.Using stellar structure and evolutionary models with modern inputphysics, tests on the extent of convection in the core of the moremassive B1.5 II-III star of the system have been carried out. Both theanalysis of the logg-logTeff diagram and the apsidal motionstudy indicate a star with a larger convective core, and thus morecentrally condensed, than currently assumed. This has been quantified inform of an overshooting parameter with a value ofαov~0.6+/-0.1. Finally, the tidal evolution of thesystem (synchronization and circularization times) has also beenstudied. Orbital elements of binary systems with a chemically peculiar starWhen binary systems with a chemically peculiar (CP) star are comparedwith normal-star binary systems, they present: a lower incidence, adeficiency of short periods, rather eccentric orbits, and companions oflow mass. Unfortunately these results are based on a relatively small (~ 50) number of CP-star binary systems with known orbital parameters anda similar analysis has not yet been carried out for helium-peculiarstars, as there is only one helium-weak star with known orbitalelements. With the aim to contribute to the study of binary systemswhose brightest component is a CP star, we have performed spectroscopicobservations and determined the orbital elements for seven of thesesystems. Of these we have included two helium-weak and two helium-strongstars. The values found for the orbital elements confirm the deficiencyof short periods and the lack of circular orbits for CP stars: only HD15144 has an orbital period shorter than 3 days (the orbital perioddistribution of normal stars peaks at 3 days) and a circular orbit. Asto helium-peculiar stars, we have determined orbital periods longer than12 days and large eccentricity values (0.26-0.40). As O-A star binarysystems have circular orbits only when their orbital periods are lessthan two days, we conclude that CP-star binary systems are characterisedonly by long orbital periods with respect to normal stars. Probably asmall component separation and/or a massive companion, which areassociated with short orbital periods, is responsible for such a strongatmospheric mass motion on the stellar surface to prevent the elementseparation which is at the basis of the CP star phenomenon. Theamplitude of the radial velocity curve of the helium-strong star HD36485 is only 8 km s(-1) , one of the smallest known values for a CPstar, which appears to be consistent with the small ( ~ 10(deg) )inclination of the rotational axis. Partially based on observationscollected at the European Southern Observatory, LaSilla Chile. The nature of visual components in 82 multiple systems.Not Available Near infrared imaging and spectroscopy of the IRAS 20126+4104 regionIn this paper we present near-infrared images and K'-band spectra(1.95-2.30 microns ) of the nebulae located in the IRAS 20126+4104region. We find bright cometary shaped objects to the Northwest of theIRAS position and other emission line objects to the Southeast. We havedetected 6 low excitation emission lines of molecular hydrogen, andpresent spatially resolved excitation temperatures, 1-0 S(1)/2-1 S(1)line ratios and ortho-para ratios for the brighter emission line objectsnear the IRAS source. The integrated flux in the H2 1-0 S(1)line of the brighter object located to the Northwest of the IRASposition is 6.85 *E(-13) erg cm(-2) s(-1) , integrated within anaperture of 10.2 arcsec(2) . >From a spectrophotometric analysis, weconclude that the H2 emission observed in this nebula ismainly produced by collisional excitation combined with fluorescentH2 emission. However, it is unclear from our observationswhether the UV radiation field that would be responsible for thefluorescent component is produced by the IRAS source itself, or by thestars embedded at the Eastern edges of two of the observedcondensations. Based on observations obtained at the ObservatorioAstronomico Nacional at San Pedro Martir, B.C. Mexico Flux Distributions for 59 Stars in CygnusAbsolute flux distributions are given for 59 Cygnus stars in thespectral range of 320--720 nm with a step of 5 nm. Their rms errors areon the average 2--4%. The synthetic color indices calculated for theflux distributions are compared with the observed color indices in threephotometric systems. Mesures de vitesses radiales. VIII. Accompagnement AU sol DU programme d'observation DU satellite HIPPARCOSWe publish 1879 radial velocities of stars distributed in 105 fields of4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbachet al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90}using the Fehrenbach objective prism method. Table 1 only available inelectronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html The ROSAT all-sky survey catalogue of optically bright OB-type stars.For the detailed statistical analysis of the X-ray emission of hot starswe selected all stars of spectral type O and B listed in the Yale BrightStar Catalogue and searched for them in the ROSAT All-Sky Survey. Inthis paper we describe the selection and preparation of the data andpresent a compilation of the derived X-ray data for a complete sample ofbright OB stars. 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. Incidence of X-ray sources among magnetic chemically peculiar starsCash & Snow (1982) and Golub et al. (1983) have detected X-rayemission from 3 out of 7 observed magnetic chemically peculiar (CP)stars. Although the incidence of X-ray sources apparently is very high,these authors concluded that such emission is not unquestionable becauseof the presence of a companion. To determine the incidence of X-raysources among hot CP stars, I have checked the list of B-type starsmeasured by Grillo et al. (1992) selecting 90 stars. Of the 4 magneticCP stars showing X-ray emission 3 are members of a binary system. Thusit appears that detectable X-ray emission from magnetic CP stars is notvery common and still questionable. To find out whether HD 37017presents X-ray emission (Drake et al. 1987) or not (Grillo et al. 1992),I have analyzed an HRI frame from the ROSAT satellite finding noevidence for X-ray emission at this star's position. Improved Mean Positions and Proper Motions for the 995 FK4 Sup Stars not Included in the FK5 ExtensionNot Available Corrections to the right ascension to be applied to the apparent places of 1217 stars given in "The Chinese Astronomical Almanach" for the year 1984 to 1992.Not Available An Einstein Observatory SAO-based catalog of B-type starsAbout 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars. The frequency and formation mechanism of B2-B5 main-sequence binariesTwenty coude spectra were obtained for each of the 74 B2-B5 IV or Vstars, and the results of their radial velocities were combined withthose of a previous study of 42 similar stars, to examine the frequencyand the formation mechanism of these binaries. New improved orbitalelements are listed for nine known double-lined and 26 single-linedspectroscopic binaries. It is found that, systems with periods of 0.01yr to 100,000 yrs, have secondary frequencies that fit the Salpeter(1955) luminosity function (but not the van Rhijn function), indicatingthat these systems were formed primarily by capture. For systems withperiods shorter than 0.01 yr, the separations of components are only afew stellar radii, suggesting that these systems have undergone masstransfer; their secondary masses have no direct information concerningthe formation mechanism. Spectroscopic binaries - 15th complementary catalogPublished observational data on the orbital characteristics of 436spectroscopic binaries, covering the period 1982-1986, are compiled intables. The data sources and the organization of the catalog are brieflydiscussed, and notes are provided for each item. Observations of interstellar diffuse absorption band at 4430 AObservations of the interstellar diffuse absorption band at 4430 A for800 O and B stars in Neckel's (1967) catalog are being carried out, and482 spectra obtained up to September 1983 have been reduced. It isconfirmed that the strength of the interstellar diffuse absorption bandat 4430 A does not simply relate to the abundance of interstellar grainson the line of sight. The relation between the color excess E(B-V) andthe equivalent width of the band to the direction of l = 130-140 deg andb = -5 to +5 deg shows that some parameter(s) other than E(B-V) is (are)needed to understand the cause of this band. Catalog of O-B stars observed with Tokyo Meridian CircleA catalog of the O-B stars, selected from 'Blaauw-Parenago' list andRubin's catalog, has been compiled on the FK4 system by the observationsmade with Gautier 8-inch Meridian Circle at the Tokyo AstronomicalObservatory during the period, 1971 to 1979. It contains 1059 stars andwas compiled for the future establishment of high precision propermotions of O-B stars. A catalog of ultraviolet interstellar extinction excesses for 1415 starsUltraviolet interstellar extinction excesses are presented for 1415stars with spectral types B7 and earlier. The excesses with respect to Vare derived from Astronomical Netherlands Satellite (ANS) 5-channel UVphotometry at central wavelengths of approximately 1550, 1800, 2500, and3300 A. A measure of the excess extinction in the 2200-A extinction bumpis also given. The data are valuable for investigating the systematicsof peculiar interstellar extinction and for studying the character of UVinterstellar extinction in the general direction of stars for which theextinction-curve shape is unknown. The local system of early type stars - Spatial extent and kinematicsPublished uvby and H-beta photometric data and proper motions arecompiled and analyzed to characterize the structure and kinematics ofthe bright early-type O-A0 stars in the solar vicinity, with a focus onthe Gould belt. The selection and calibration techniques are explained,and the data are presented in extensive tables and graphs and discussedin detail. The Gould belt stars of age less than 20 Myr are shown togive belt inclination 19 deg to the Galactic plane and node-lineorientation in the direction of Galactic rotation, while the symmetricaldistribution about the Galactic plane and kinematic properties (purecircular differential rotation) of the belt stars over 60 Myr oldresemble those of fainter nonbelt stars of all ages. The unresolveddiscrepancy between the expansion observed in the youngest nearby starsand the predictions of simple models of expansion from a point isattributed to the inhomogeneous distribution of interstellar matter. Be stars in binariesThe known companions to 80 Be stars and 355 B stars listed in the BrightStar Catalogue in the range B1-B7 III-V and north of delta = -30 deg areconsidered. The known near-absence of Be binaries with periods less than1/10 yr is confirmed. For longer periods up to the limit of 10,000 AU ofthis survey, the Be and B stars do not differ in binary frequencies.This result implies that during pre-main-sequence contraction, the tidalbraking in binaries wider than 0.5 AU was inadequate to prevent theformation of stars with nearly the break-up rotational velocities. Thefraction of Be and B stars that have companions is higher in clustersand associations (38 percent) than among field stars (25 percent),confirming that escapees from clusters tend to be single stars. There issome evidence that the companions of Be stars that occur in the sameluminosity range tend also to be Be stars; that result was expectedbecause in visual binaries there is a known tendency for rapidlyrotating primaries to have rapidly rotating secondaries. The Spectroscopic Binary HD189178Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1982PASP...94..515B&db_key=AST The interstellar 2200 A band - A catalogue of equivalent widthsNot Available A comparison of the orbital inclinations of the spatially close spectroscopic double starsThe 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. Structure and age of the local association /Pleiades group/Intermediate-band indices are used to derive luminosities for some 500early-type stars with well-determined proper motions and radialvelocities. Space motion vectors and galactic coordinates are computedfor the stars considered. It is found that the local association membersare mainly concentrated in the Sco-Cen region in the Southern Hemisphereand the Cas-Tau region in the north. Classification of intrinsic variables. VI - Ultrashort-period, very small amplitude B-type variablesThese very young disk-population variables are found to be distributedin a very narrow instability strip, extending from M(bol) = -9 mag to -3mag and including stars with a range of at least 25 to 5 solar masses.Some new variables, for which periods are not yet available, aresuggested as possibly filling the existing gaps in the luminositydistribution and extending the instability region to still lower masses. Absolute ultraviolet spectrophotometry from the TD1 satellite. II. Observations of B star continua shortward of 2500 angstrom.Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&A....29..211V&db_key=AST
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