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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.
| Orbital solutions for SB2 systems with a HgMn component
From a new set of spectroscopic observations we determined orbitalparameters of six SB2 systems with one or both components being HgMnstars.We slightly refined the orbital periods for HD 32964,HD 173524, HD 174933 andHD 216494. Our results for HD 358are in agreement with the previous literature studies. RegardingHD 33647, our orbital period is shorter than previousdeterminations. HD 173524 is a triple system. Fromthe variations of the γ-velocity deduced from our and literaturedata, we refined the orbital period and we estimated the eccentricity ofthe third companion, for which we get e ≈ 0.13 and Porb =36 ± 3 years. HD 191110 and HD216494 seem to be the only synchronous SB2 within our sample.Following the hypothesis of rotational axes perpendicular to the orbitalplane, we estimated the angle of the orbital plane to the line of sight.We identified in our spectra the signature of the Hβ ofthe third component of HD 216494 and we highlight aslight variation of the γ-velocity due to the presence of thiscomponent.Based on observations collected at the Stellar Station ``M. G.Fracastoro'' of the Catania Astrophysical Observatory, Italy.Appendix A is only available in electronic form athttp://www.edpsciences.org
| Rotational Velocities of B, A, and Early-F Narrow-lined Stars
Projected rotational velocities for 58 B, A, and early-F stars have beendetermined from high-resolution spectroscopic observations made at KittPeak National Observatory with the coudé feed telescope. All thestars are slowly rotating with vsini<60 km s-1. Because oftheir low rotational velocities, 15 of the stars have been observed asprospective, early-type, radial velocity standards.
| 3D mapping of the dense interstellar gas around the Local Bubble
We present intermediate results from a long-term program of mapping theneutral absorption characteristics of the local interstellar medium,motivated by the availability of accurate and consistent parallaxes fromthe Hipparcos satellite. Equivalent widths of the interstellar NaID-line doublet at 5890 Å are presented for the lines-of-sighttowards some 311 new target stars lying within ~ 350 pc of the Sun.Using these data, together with NaI absorption measurements towards afurther ~ 240 nearby targets published in the literature (for many ofthem, in the directions of molecular clouds), and the ~ 450lines-of-sight already presented by (Sfeir et al. \cite{sfeir99}), weshow 3D absorption maps of the local distribution of neutral gas towards1005 sight-lines with Hipparcos distances as viewed from a variety ofdifferent galactic projections.The data are synthesized by means of two complementary methods, (i) bymapping of iso-equivalent width contours, and (ii) by densitydistribution calculation from the inversion of column-densities, amethod devised by Vergely et al. (\cite{vergely01}). Our present dataconfirms the view that the local cavity is deficient in cold and neutralinterstellar gas. The closest dense and cold gas ``wall'', in the firstquadrant, is at ~ 55-60 pc. There are a few isolated clouds at closerdistance, if the detected absorption is not produced by circumstellarmaterial.The maps reveal narrow or wide ``interstellar tunnels'' which connectthe Local Bubble to surrounding cavities, as predicted by the model ofCox & Smith (1974). In particular, one of these tunnels, defined bystars at 300 to 600 pc from the Sun showing negligible sodiumabsorption, connects the well known CMa void (Gry et al. \cite{gry85}),which is part of the Local Bubble, with the supershell GSH 238+00+09(Heiles \cite{heiles98}). High latitude lines-of-sight with the smallestabsorption are found in two ``chimneys'', whose directions areperpendicular to the Gould belt plane. The maps show that the LocalBubble is ``squeezed'' by surrounding shells in a complicated patternand suggest that its pressure is smaller than in those expandingregions.We discuss the locations of several HI and molecular clouds. Usingcomparisons between NaI and HI or CO velocities, in some cases we areable to improve the constraints on their distances. According to thevelocity criteria, MBM 33-37, MBM 16-18, UT 3-7, and MBM 54-55 arecloser than ~ 100 pc, and MBM 40 is closer than 80 pc. Dense HI cloudsare seen at less than 90 pc and 85 pc in the directions of the MBM 12and MBM 41-43 clouds respectively, but the molecular clouds themselvesmay be far beyond. The above closest molecular clouds are located at theneutral boundary of the Bubble. Only one translucent cloud, G192-67, isclearly embedded within the LB and well isolated.These maps of the distribution of local neutral interstellar NaI gas arealso briefly compared with the distribution of both interstellar dustand neutral HI gas within 300 pc.Tables 1 and 2 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp:cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/411/447
| Catalogue of averaged stellar effective magnetic fields. I. Chemically peculiar A and B type stars
This paper presents the catalogue and the method of determination ofaveraged quadratic effective magnetic fields < B_e > for 596 mainsequence and giant stars. The catalogue is based on measurements of thestellar effective (or mean longitudinal) magnetic field strengths B_e,which were compiled from the existing literature.We analysed the properties of 352 chemically peculiar A and B stars inthe catalogue, including Am, ApSi, He-weak, He-rich, HgMn, ApSrCrEu, andall ApSr type stars. We have found that the number distribution of allchemically peculiar (CP) stars vs. averaged magnetic field strength isdescribed by a decreasing exponential function. Relations of this typehold also for stars of all the analysed subclasses of chemicalpeculiarity. The exponential form of the above distribution function canbreak down below about 100 G, the latter value representingapproximately the resolution of our analysis for A type stars.Table A.1 and its references are only available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/407/631 and Tables 3 to 9are only available in electronic form at http://www.edpsciences.org
| 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.
| Search for spectroscopical signatures of transiting HD 209458b's exosphere
Following recent attempts to detect the exosphere of the extra-solarplanet 51 Pegb in the infrared (Coustenis et al. \cite{cou97},\cite{cou98}; Rauer et al. \cite{rau00a}), we discuss here a search foroptical spectroscopic signatures from a gaseous extended envelope(called exosphere) surrounding the planet HD 209458b. This planet has ademonstrated photometric transit (Charbonneau et al. \cite{cha00a};Henry et al. \cite{hen00}), thus offering an increased probability forthe spectroscopic detection of such an envelope. Therefore it is thebest known candidate for probing the exospheric composition of a giantplanet, orbiting a Sun-like star at a short distance. The observationswere performed with UVES at the VLT and cover most of the 328-669 nmrange. We did not detect HD 209458b's exosphere at a level of 1%, avalue close to the predictions. We discuss here the first resultsobtained and their limitations, as well as future prospective. Based onpublic data from the UVES Commissioning at the ESO 8.2~m Kueyentelescope operated on Paranal Observatory, Chile.
| Mercury Elemental and Isotopic Abundances in Mercury-Manganese Stars
Hg II abundances have been determined for 42 mercury-manganese (HgMn)stars by fitting synthetic spectra to observed spectra of the 3984Å Hg II line. Twenty of the stars had lines sharp enough to allowtheir Hg isotopic abundance mixes to be estimated. The Hg abundance isreported for more HgMn stars here than in any other single work. Nocorrelation was found between Hg II abundance and T_eff or the meancentral wavelength of HgMn lambda3984 stars. The mean central wavelengthof lambda3984 , an indicator of the Hg isotopic mix, is looselycorrelated with T_eff: stars with primarily heavy Hg isotopes tend to becooler, although one star, 46 Aql, has almost pure ^204Hg and T_eff inabout the middle of the temperature range for HgMn stars. We find thatthere is no evidence that any of the HgMn stars have ^196Hg or ^198Hg.For the very sharp-lined stars, the ^204Hg abundance decreases withincreasing T_eff. No correlation is seen between the mean centralwavelength and the surface gravity. No correlation was found between theprojected rotational velocity and the Hg II abundance or the centralwavelength of lambda3984, although this result may be biased by theselection of stars with low reported vsini. Hg I lambda4358 was measuredat high spectral resolution for seven HgMn stars. The isotopic shiftsare too small, and the hyperfine components are too weak to allowunambiguous isotopic abundance ratios to be found. Hg I abundancescorrelate fairly well with Hg II abundances. Some of the Hg isotopicmixtures are difficult to explain using only diffusion. HR 7245 hasapproximately equal abundances of ^199Hg, ^200Hg, ^202Hg, and ^204Hg butvery little ^201Hg, and 11 Per has Hg that is mostly ^199Hg and ^204Hg.Calculations show that hyperfine splitting of ^201Hg changes theradiative forces it feels compared with other isotopes, which may alterdiffusion of that isotope enough to explain its absence in HR 7245, butwe have found no possible explanation for the Hg isotopic mix found in11 Per. These are the first very high resolution measurements of Hg IIlambda3984 for HR 7245 and 11 Per. Although diffusion may be acting inHgMn stars, either there are one or more other mechanisms acting to helpproduce the overabundances and isotopic mixtures seen or ourunderstanding of diffusion is lacking on some important point.
| Search for magnetic fields in HgMn stars by using relative strengths of multiplet 74 Fe II lines
The anomalous strength of the Fe II lambda 6147.7 line relative to Fe IIlambda 6149.2 in the stars with magnetic fields is used for detectingmagnetic fields in very slowly rotating HgMn stars. The diagnosis basedon this pair of magnetically sensitive Fe lines is a simple and fasttool, but its application to more rapidly rotating HgMn stars ishampered by blending with Hg II lambda 6149.5. For spectra ofsharp-lined HgMn stars (with v sin i<4 km s(-1) ) taken at highresolving power (R>= 100 000) both lines, Fe II lambda 6149.25 and HgII lambda 6149.48, become fully unblended. The observed relativedifferences between the equivalent widths of the two Fe II lines arecompared with those derived from synthetic spectra computed byneglecting magnetic field effects. This comparison has shown that threeHgMn stars, HD 175640, HD 178065 and HD 186122 are very likely topossess a magnetic field that could be larger than 2 kG. Based onobservations obtained at the European Southern Observatory, La Silla,Chile (ESO programme No.~61.D-0480)
| Isotopic composition of HG and Pt in 5 slowly rotating HgMn stars
Theoretical models addressing the origin of peculiarities in the spectraof HgMn stars have not been sufficiently constrained so far by theavailable abundance data. Previous studies of Hg and Pt in samples ofHgMn stars often relied on spectra of rather low resolution and low S/Nratio, so that only limited information could be derived from thecentroid wavelength of unresolved isotopic blends. In this paper wepresent the results of a study of the isotopic compositions of Hg and Ptin 5 very slowly rotating HgMn stars. This work represents animprovement over previous studies due to the availability of very highspectral resolution (R = 118 000) and to the new information onwavelengths and atomic structure of Hg II and Pt II. Each of theobserved stars has Hg overabundant by more than 5 dex compared with thesolar abundance. The largest overabundance of Pt (4.59 dex) was found inthe star HD 193452. No star shows terrestrial isotopic proportions. Themost pronounced deviation from the terrestrial composition is found inthe stars HD 141556 and HD 193452, which are the coolest ones in oursample. Based on observations obtained at the European SouthernObservatory, La Silla, Chile (ESO programme No.~58.D-0654)
| Isotopic composition of HG and Pt in slowly rotating HgMn stars
Preliminary results from a study of the isotopic compositions of theelements Hg and Pt in a number of HgMn stars are presented. This workrepresents an improvement over previous studies thanks to the very highspectral resolution available (R = 118 000) and to the new informationon wavelengths and atomic structure of Hg II and Pt II.
| HgMn stars: new insights
Recent results obtained by various authors on the properties of HgMnstars are reviewed. Substantial progress has been achieved in the studyof abundances and isotopic anomalies. The results about the magneticfields and membership in multiple systems suggest further directions ofinvestigations to be followed in view of answering the question of thedevelopment of abundance peculiarities in HgMn stars.
| Mass determination of astrometric binaries with Hipparcos. III. New results for 28 systems
This paper is the third of a series devoted to the determination ofstellar masses from Hipparcos data. This is a continuation of Martin etal. (1997), who introduced the theory and assessed the performance ofthe method from simulated data, and of a second paper with the firstresults for 46 systems, ( te[Martin & Mignard 1998]{Mar98}). Theorbit file maintained by the CHARA group and new publications of orbitalelements made the processing of 70 additional candidate systemspossible, including 28 of the 145 systems already tested in the previouswork. Significant results were obtained on 22 systems, with relativeaccuracy better than 25% for the masses of 17 binaries. New estimatesare also given for 6 systems previously investigated, thanks to reliablevalues of the magnitude difference from the Hipparcos catalogue ( te[ESA1997]{ESA97}). New orbital elements are proposed for HIP 12623 (12Persei) from speckle/spectroscopic measurements. Results are discussedfor each system, alongside the mass-luminosity relation based onHipparcos magnitudes and distances.
| 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
| The observed periods of AP and BP stars
A catalogue of all the periods up to now proposed for the variations ofCP2, CP3, and CP4 stars is presented. The main identifiers (HD and HR),the proper name, the variable-star name, and the spectral type andpeculiarity are given for each star as far as the coordinates at 2000.0and the visual magnitude. The nature of the observed variations (light,spectrum, magnetic field, etc.) is presented in a codified way. Thecatalogue is arranged in three tables: the bulk of the data, i.e. thosereferring to CP2, CP3, and CP4 stars, are given in Table 1, while thedata concerning He-strong stars are given in Table 2 and those foreclipsing or ellipsoidal variables are collected in Table 3. Notes arealso provided at the end of each table, mainly about duplicities. Thecatalogue contains data on 364 CP stars and is updated to 1996, October31. This research has made use of the SIMBAD database, operated at CDS,Strasbourg, France.
| The HR-diagram from HIPPARCOS data. Absolute magnitudes and kinematics of BP - AP stars
The HR-diagram of about 1000 Bp - Ap stars in the solar neighbourhoodhas been constructed using astrometric data from Hipparcos satellite aswell as photometric and radial velocity data. The LM method\cite{luri95,luri96} allows the use of proper motion and radial velocitydata in addition to the trigonometric parallaxes to obtain luminositycalibrations and improved distances estimates. Six types of Bp - Apstars have been examined: He-rich, He-weak, HgMn, Si, Si+ and SrCrEu.Most Bp - Ap stars lie on the main sequence occupying the whole width ofit (about 2 mag), just like normal stars in the same range of spectraltypes. Their kinematic behaviour is typical of thin disk stars youngerthan about 1 Gyr. A few stars found to be high above the galactic planeor to have a high velocity are briefly discussed. Based on data from theESA Hipparcos astrometry satellite and photometric data collected in theGeneva system at ESO, La Silla (Chile) and at Jungfraujoch andGornergrat Observatories (Switzerland). Tables 3 and 4 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| ICCD Speckle Observations of Binary Stars. XVII. Measurements During 1993-1995 From the Mount Wilson 2.5-M Telescope.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.1639H&db_key=AST
| Binary Star Orbits from Speckle Interferometry. XI. Orbits of Twelve Lunar Occultation Systems.
Stars detected as double by lunar occultation are logical targets forspeckle interferometric and spectroscopic investigations. This paperpresents twelve orbits for interferometric systems; eight of these hadno previous orbits and the other four have new orbit determinationswhich represent improvements on previously published elements. Wheretrigonometric parallaxes are not available, spectroscopic parallaxes arecalculated, and model-dependent masses are determined for ten componentswhose results seem most reasonable.
| 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
| ICCD Speckle Observations of Binary Stars.XV.An Investigation of Lunar Occultation Systems
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....112.2260M&db_key=AST
| 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.
| Speckles and Shadow Bands
Speckle interferometry has for the past two decades provided a means tomeasure very accurate relative positions of binary stars, data crucialto the fundamental determination of basic stellar parameters. As atechnique for observing small angular separations speckle interferometryis exceeded only by long baseline interferometry (a technique still ininfancy) and the observation of lunar occultation phenomena. As the moonpasses in front of stars the light coming from those stars is occulted.Occultations of binary stars can determine relative intensities and canmeasure separations which are comparable to those measured bylong-baseline interferometers. The data are difficult to interpret sincethe measured separation is a projection of the true angular separationand non-standard filters are often used. No complete listing of alloccultation measures has been published since the compilation of DavidEvans (IAU Colloquium No. 62, Current Techniques in Double and MultipleStar Research, Lowell Observatory Bulletin No. 167, 1981, eds.Harrington, R.A. \& Franz, O.G., Lowell Observatory, Flagstaff). Thedissertation presents 772 measures of 357 systems, an increase of 60\%over the Evans catalog. The methodology of speckle interferometry ispresented, followed by 362 re-reduction measures and 253 new measures.The re-reduction measures were cases where prior analysis showed nocompanion. With improved reduction algorithms, detection frequencysignificantly increased. One observation in eight previously showing nocompanion produced a measurable result. Results were obtained with the1.8-m Perkins telescope of Lowell Observatory, the 2.5-m Hookertelescope of Mt. Wilson Observatory, the 3.8-m Mayall telescope of KittPeak National Observatory and the 4.0-m telescope at Cerro TololoInterAmerican Observatory. All but 130 of the occultation objects havespeckle observations. The likelihood of future detection by speckle isconsidered. An analysis of 131 negative results is presented. Of theremaining 96 systems, 66 have been detected by speckle interferometry,13 for the first time, and 17 new orbits have been calculated. Of theseorbits, five (HR 793 = Bla Aa, ADS 3608 = A 1844, HR 3880 = McA 34, HR5652 = B 2531 Aa, HR 7776 = $\beta$ Cap) have improved elements overprevious orbit calculations, four (BD$+$24~1805 = Cou 929, ADS 17052 = A2700, HR 9041 = Fin 359, ADS 17111 = A 2100) have previous butsignificantly different orbits, five (HR 132 = McA 1 Aa, HR 1808 = McA19 Aa, HR 2343 = Btz Aa, HR 8060 = Fin 328, HR 8704 = McA 73) are firstorbits, and three (HR 763 = McA 7, HR 2130 = McA 24, HR 2846 = McA 30Aa) are first orbits of spectroscopic binaries. The occultation catalog,speckle measures, and new orbits will be presented in subsequent CHARApublications. The detection of occultation binaries by speckleinterferometry seems to be predictable, however, there appear to be asmall sample of occultation binaries which cannot be detected. These maybe spurious. Lunar occultation measures place a good limit on $\Delta$mfor speckle of about 3.0. CHARA hopes to complete a survey of alloccultation objects with current scheduled runs which should result in afurther five to ten objects resolved for the first time. While the rateof occultation measures has dropped significantly, they are stillcontinuing to provide useful complementary data for other binary starmethods. (SECTION: Dissertation Summaries)
| Some remarks on the origin of the abundance anomalies in HgMn stars.
Not Available
| 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.
| Magnetic fields of the HgMn spectroscopic binaries χ LUPI and 74 Aquarii.
A quadratic magnetic field of 3.6 kG has been discovered in the primarycomponent of 74 Aqr, and a longitudinal magnetic field of -274G has beenmeasured in the secondary of χ Lup. These two stars are SB2's with aHgMn primary. It is the first time that magnetic fields are definitelydetected in such objects. This has potentially important implicationsfor the understanding of the physical processes occurring inmain-sequence A and B stars.
| A new list of effective temperatures of chemically peculiar stars. II.
Not Available
| Catalogue of CP stars with references to short time scale variability
A catalogue was compiled which contains all references in the literaturesince 1962 related to variations of CP stars on time scales shorter thanthe rotation period. The role of this catalogue lies in the unbiasedlisting of all available references, and not in a critical evaluation.
| Speckle observations of visual and spectroscopic binaries. V.
Not Available
| Relative Orientation of Angular Momenta in Multiple Stellar Systems
Not Available
| All-sky Stromgren photometry of speckle binary stars
All-sky Stromgren photometric observations were obtained for 303 specklebinaries. Most stars were in the range of V = 5-8. These data, whencombined with ratios of intensities from the CHARA speckle photometryprogram, will allow the determination of photometric indices for theindividual components of binary stars with separations as small as 0.05arcsec. These photometric indices will complement the stellar massesfrom the speckle interferometry observations to provide a much improvedmass-luminosity relationship.
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Osservazione e dati astrometrici
| Costellazione: | Acquario |
| Ascensione retta: | 22h53m28.70s |
| Declinazione: | -11°37'00.0" |
| Magnitudine apparente: | 5.8 |
| Distanza: | 201.613 parsec |
| Moto proprio RA: | 22 |
| Moto proprio Dec: | 2 |
| B-T magnitude: | 5.694 |
| V-T magnitude: | 5.769 |
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