Evolution of interacting binaries with a B type primary at birth
We 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.
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Search for forced oscillations in binaries. IV. The eclipsing binary V436 Per revisited
An analysis of new spectroscopic and photoelectric U B V observations,satisfactorily covering the whole orbital period of V436 Per, togetherwith existing data allowed us to improve the knowledge of the basicphysical characteristics of the binary and its components. In severalaspects, our new results differ from the findings of Paper I of thisseries: in particular, we found that it is the star eclipsed in thesecondary minimum which is slightly more massive and larger than theoptical primary. We also conclude that the apsidal advance - if presentat all - is much slower than that estimated in a previous study. Theorbital period might be increasing by 0.28 s per year but also thisfinding is very uncertain and needs verification by future observations.It is encouraging to note that two completely independent sets ofprograms for light-curve solutions lead to identical results. A notablefinding is that both binary components rotate with very similar - if notidentical - rotational periods of 1d.45 and 1d.40,much shorter than what would correspond to a 10d.9 spin-orbitsynchronization period at periastron. Rapid line-profile changesreported earlier could not be confirmed from new, dedicated series ofhigh-resolution and S/N spectra.This research is based on spectra from the Dominion AstrophysicalObservatory (DAO), Ondřejov, and Thuringer Landessternwarte (TLS)Tautenburg.
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Rotational Velocities of B Stars
We 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.
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The proper motions of fundamental stars. I. 1535 stars from the Basic FK5
A direct combination of the positions given in the HIPPARCOS cataloguewith astrometric ground-based catalogues having epochs later than 1939allows us to obtain new proper motions for the 1535 stars of the BasicFK5. The results are presented as the catalogue Proper Motions ofFundamental Stars (PMFS), Part I. The median precision of the propermotions is 0.5 mas/year for mu alpha cos delta and 0.7mas/year for mu delta . The non-linear motions of thephotocentres of a few hundred astrometric binaries are separated intotheir linear and elliptic motions. Since the PMFS proper motions do notinclude the information given by the proper motions from othercatalogues (HIPPARCOS, FK5, FK6, etc.) this catalogue can be used as anindependent source of the proper motions of the fundamental stars.Catalogue (Table 3) is only available at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strastg.fr/cgi-bin/qcat?J/A+A/365/222
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Mapping the contours of the Local bubble: preliminary results
We present preliminary results from a long-term program of mapping theneutral absorption characteristics of the local interstellar medium,taking advantage of Hipparcos stellar distances. Equivalent widths ofthe NaI D-line doublet at 5890 Å are presented for thelines-of-sight towards some 143 new target stars lying within 300 pc ofthe Sun. Using these data which were obtained at the Observatoire deHaute Provence, together with previously published NaI absorptionmeasurements towards a further 313 nearby targets, we present absorptionmaps of the distribution of neutral gas in the local interstellar mediumas viewed from 3 different galactic projections. In particular, thesemaps reveal the Local Bubble region as a low neutral densityinterstellar cavity in the galactic plane with radii between 65-250 pcthat is surrounded by a (dense) neutral gas boundary (or ``wall''). Wehave compared our iso-column contours with the contours derived bySnowden et al. (\cite{snowden98}) using ROSAT soft X-ray emission data.Consistency in the global dimensions derived for both sets of contoursis found for the case of a million degree hot LB plasma of emissivity0.0023 cm(-6) pc with an electron density of 0.005 cm(-2) . We havedetected only one relatively dense accumulation of cold, neutral gaswithin 60 pc of the Sun that surrounds the star delta Cyg, and note thatthe nearest molecular cloud complex of MBM 12 probably resides at thevery edge of the Local Bubble at a distance of ~ 90 pc. Our observationsmay also explain the very different physical properties of the columnsof interstellar gas in the line-of-sight to the two hot stars epsilonCMa and beta CMa as being due to their locations with respect to theBubble contours. Finally, in the meridian plane the LB cavity is foundto be elongated perpendicularly to the Gould's Belt plane, possiblybeing ``squeezed'' by the expanding shells of the Sco-Cen andPerseus-Taurus OB associations. Tables 1 and 2 are also available inelectronic form at the CDS (Strasbourg) via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
The Hipparcos photometry of the Chemically Peculiar main sequence B, A,and F stars is examined for variability. Some non-magnetic CP stars,Mercury-Manganese and metallic-line stars, which according to canonicalwisdom should not be variable, may be variable and are identified forfurther study. Some potentially important magnetic CP stars are noted.Tables 1, 2, and 3 are available only in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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HD 6226: a new bright B variable with occasional brightenings. Is it an unrecognized Be star?
An analysis of differential UBV measurements of HD 6226 secured between1982 and 1995 at Hvar, and combined with the Hipparcos satellite H_pphotometry, led to the finding that this infrequently observed star is anew variable, characterized by occasional brightenings accompanied bythe reddening of the B-V, and blueing of the U-B index. We note thatsuch behaviour was found for several Be stars like QR Vul or o Cas andit would be of interest to check whether also HD 6226 is not anunrecognized Be star. A period analysis of the photometric dataindicates a possibility that the brightenings may occur periodically,with a period of 481.3 d. However, this finding needs to be tested sinceseveral other possible periods were also detected. Moreover, there is noa priori reason to believe that the brightenings must occur in regularintervals. If there is indeed a 481-d periodicity, then the nearestbrightening should occur around Nov. 27, 1998. A spectroscopic study ofthe star will be crucial for a better understanding of its nature butfurther photometric monitoring is also very desirable.
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The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
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Systematic Errors in the FK5 Catalog as Derived from CCD Observations in the Extragalactic Reference Frame.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114..850S&db_key=AST
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UBV photometry of Be stars at Hvar: 1972--1990
A summary of results of the systematic UBV photoelectric monitoring ofbright northern Be stars carried out at the Hvar Observatory between1972 and 1990 is presented. Altogether, 76 Be stars of all luminosityclasses were observed and 13,848 UBV measurements secured.Simultaneously, 9,648 UBV measurements of 48 check stars (most of themof early spectral types) were obtained. A careful transformation of allobservations into the standard Johnson system allowed detection andmonitoring of even very mild long-term light and colour variations ofthese objects. Almost all early-type Be stars in the sample turned outto be variable. For several stars phase-locked light variations relatedto their binary nature were established. Sudden brightenings, on a timescale of a few days, were detected for o Cas and QR Vul. Tables 2 and 3are only available in electronic form at CDS via ftp tocdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
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Search for forced oscillations in binaries. I. The eclipsing and spectroscopic binary V436 Persei = 1 Persei.
Outline of a project aimed at testing the presence of rapid line-profilevariations in the atmospheres of hot components of close binaries ispresented and its first results are described. An analysis of newelectronic spectra of the eclipsing binary V436 Per from threeobservatories and of photoelectric observations, obtained earlier byseveral authors, leads to a unique determination of all basic physicalelements of this interesting object. The first practical application ofa new method of spectral disentangling allowed us to obtain, for thefirst time, individual accurate line profiles of both binary componentsand to derive their rotational velocities and orbital radial-velocitycurves. We also detected absorption sub-features travelling from blue tored accross the He I 6678 line profile, in a series of six spectra takenduring one night. At least one of the components of V436 Per is,therefore, a new hot line-profile variable.
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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.
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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.
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Toward a consistent model of the B0.5IVe + sdO binary φ Persei.
A detailed analysis of a very rich collection of spectroscopic andphotometric observations of the bright Be star φ Per is presented.Earlier reports that φ Per is a double-lined spectroscopic binaryconsisting of two emission-line objects are confirmed. An orbitalsolution based on the emission-wing radial velocities for both stars hasled to a determination of the orbital elements which defines the correctorbital phases. All data since the beginning of this century can bereconciled with a constant orbital period of 126.6731d+/-0.0071d. Thenew orbital solution gives lower masses than those found by earlierinvestigators, namely M_1_sin^3^i=16.35Msun_ andM_2_sin^3^i=1.69Msun_. These masses are in agreement with therecently derived spectral classes B0.5IVe and sdO6: for the primary andsecondary, respectively. Long-term light variations are positivelycorrelated with the emission strength, and in the U-B vs. B-V diagramthe object has changed its apparent photometric type from a B supergianttoward an MS object. Dereddening of the mean seasonal UBV magnitudesfrom recent years (when spectra show the weakest recorded Balmeremission) leads to a photometric spectral type a bit earlier than B1V.An important and exciting finding is that the emission lines of bothstars have been weakening simultaneously in recent years, which seems toindicate some kind of interaction between the binary components. Thepresence of rapid light variability is confirmed, but its more detailedanalysis is postponed for another study. Low-amplitude orbital lightvariations with rather complicated light and color curves are foundafter the removal of long-term and rapid changes. The principal maximaand minima of the orbital light curves can be traced in both old and newphotometry and can probably be attributed to specific circumstellarstructures whose signatures are also seen spectroscopically. Finally,systematic secular changes in the shape and amplitude of the orbitalradial-velocity curve of the Balmer shell lines are found, based on 1024radial velocities spanning nearly a century.
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A new list of effective temperatures of chemically peculiar stars. II.
Not Available
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Physical characteristics of close binary system components
An approximate approach for evaluating the mass of invisible satellitesof close binary systems with the mass-function f(M) much less than 1 issuggested. A possibility of using it is shown for 62 close binarysystems.
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Reliable photometric reductions to the standard UBV (or uvby) system and accurate UBV magnitudes of bright standard stars from the northern part of the international Be program
A modified method of computer reduction of UBV (or uvby) photoelectricobservations to standard systems, which combines advantages of what hasso far been achieved in this area, is described in detail. A completereduction of over 46000 UBV observations obtained at Hvar Observatorybetween 1972 and 1991, and of nearly 5000 UBV observations secured atSkalnate Pleso Observatory between 1980 and 1987, was carried out usingthe new technique. It is argued that replacing the original Johnson'sUBV values for the non-variable stars that were observed by the meanvalues based on repeated observations over several years and applyingthe new reduction technique can ensure a stable reproduction of UBVmagnitudes, obviously quite close to the standard Johnson's ones, overmany years and from observatories situated at very different altitudesabove sea level within about 0.01mag in all three UBV magnitudes. A listof new accurate mean UBV values of 191 stars which were regularlyobserved at Hvar - and a part of them also at Skalnate Pleso - ascomparison, check and standard stars in the Be- and Ap-star observingprograms, is included for future use by photometric observers in theNorthern Hemisphere. For a number of these stars, we can guaranteesecular constancy within 0.mag01 during the past 5 to 15 years.
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Speckle observations of visual and spectroscopic binaries. V.
Not Available
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The Gaii Lines in the Red Spectrum of Ap-Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&A...272..465L&db_key=AST
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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
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Speckle observations of visual and spectroscopic binaries. III
This is the third paper of this series giving results of speckleobservations carried out for seven visual and 119 spectroscopic binariesat seven nights from May 20 to May 27, 1989, and for 30 visual and 272spectroscopic binaries at 12 nights from June 11 to June 15, and fromAugust 28 to September 3, 1990, using the 212-cm telescope at San PedroMartir Observatory in Mexico. Fringes in the lower spectrum of 31 visualand spectroscopic binaries with angular separation larger than 21 arcsecare obtained. Additionally to two spectroscopic binaries, HD41116 andHD206901, named in the second paper of this series, six spectroscopicbinaries are found each of which has the third component starsurrounding two stars of spectroscopic binary having periodic variationof radial velocity.
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BV photometry of the binary Be star Phi Persei
Recent photometry of Phi Per is combined with unpublished photometryfrom the last 10 years. The results show three kinds of variation: (1) along-term change in average brightness of approximately 0.05 V magnitudeover 6 yr; (2) night-to-night variability of up to 0.05 mag; and (3)abrupt minima of about 0.1 mag in amplitude. An association is foundbetween the phases of minimum light, increased strength of the sharphydrogen-absorption cores, and the ascending branches of theradial-velocity curve of the sharp hydrogen-absorption cores. The lightminima appear to be caused by periodic variations in the opacity of thecircumstellar material, not eclipses or intrinsic stellar variation.Disk and gas-stream models of the circumstellar material are consideredin relation to the photometry.
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Fourth preliminary catalogue of stars, right ascension observed with photoelectric transit instrument (PPCP4).
Not Available
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Physical data of the fundamental stars.
Not Available
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Close binaries observed polarimetrically
Not Available
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MK classification and photometry of stars used for time and latitude observations at Mizusawa and Washington
MK spectral classifications are given for 591 stars which are used fortime and latitude observations at Mizusawa and Washington. Theclassifications in the MK system were made by slit spectrograms ofdispersion 73 A/mm at H-gamma which were taken with the 91 cm reflectorat the Okayama Astrophysical Observatory. Photometric observations in UBV were made with the 1-meter reflector at the Flagstaff Station of U.S.Naval Observatory. The spectrum of HD 139216 was found to show a strongabsorption line of H-beta. The following new Am stars were found:HD9550, 25271, 32784, 57245, 71494, and 219109. The following new Apstars were found: HD6116, 143806, 166894, 185171, and 209260. The threestars, HD80492, 116204, and 211376, were found to show the emission inCaII H and K lines.
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Third preliminary catalogue of stars observed with the photoelectric astrolabe of the Beijing Astronomical Observatory.
Not Available
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A catalogue of right ascensions and declinations of FK4 stars
The position parameters of 578 stars from the fundamental catalog FK4are determined on the basis of 3-4-h meridian-circle observationsobtained by the differential method at Belgrade Astronomical Observatoryduring 1981-1987. The observation method and data-reduction proceduresare explained, and the results are compiled in extensive tables. Theaverage mean-square errors per observation are found to beepsilon(alpha) cos delta = + or - 0.022 sec and epsilon(delta) = + or -0.32 arcsec.
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The equal-altitude method of quasi-absolute determination of star coordinates
Absolute coordinate values are determined for 86 objects on the basis ofdata obtained with Mark II photoelectric astrolabe No. 2 at BeijingAstronomical Observatory during the period 1979-1984. The equal-altitudemethod employed in the computations is described in detail, and theresults are presented in tables. The mean accuracy of the positioncorrections is given as + or - 1.6 msec in right ascension and + or -0.019 arcsec in declination.
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Two catalogues of FK4 right-ascension corrections and their application
The results of observations conducted as part of the regular timeservice with transit instruments at the Borowiec and BratislavaObservatories were used to work out catalogs of right-ascensioncorrections of the FK4 stars, included in the observational programs.The characteristics of both catalogs are presented in the paper.Comparisons between the catalogs as well as their comparison with thecompilation catalog produced on the basis of observations performed withastrolabes are given. The results of applying these right-ascensioncorrections to the re-reduction of universal time are also presented.
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INHABITED SKY
