New runaway OB stars with HIPPARCOS
A Monte Carlo method for detection of runaway OB stars fromobservational data is proposed. 61 runaway OB star candidates have beendetected by an analysis of Hipparcos proper motions. The peculiartangential and total transverse velocities have been determined forthese stars. A list of the detected runaway star candidates ispresented. The evidence of a discrepancy between photometric andparallactic distances of runaway OB star candidates is presented.
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Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 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
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Mining in the HIPPARCOS raw data
The Hipparcos solutions flagged as unreliable after the completion ofthe standard data processing have been systematically revisited in thelight of additional information, primarily related to theirmultiplicity. In many cases improved solutions have been obtained,yielding at the same time an Hipparcos based separation and positionangle and a better astrometric solution for the system. The principlesapplied in this reprocessing are explained and more than a hundred newsolutions with absolute and relative astrometry are presented anddiscussed. Tables 1 to 7 are also 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
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Dust shells around certain early-type stars with emission lines.
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New Perspectives on AX Monocerotis
AX Moncerotis is a 232d, noneclipsing, interacting binary star thatconsists of a K giant, a Be-like giant, and large amounts ofcircumstellar material. The K star is almost certainly a synchronousrotator and is probably in contact with its critical lobe. The Be starwas believed to be a rapid rotator based on extremely wide absorptionlines, but new spectra show that these lines arise from thecircumstellar environment. Hydrogen emission, also circumstellar, ismany times stronger than the continuum. Near-ultraviolet light curvesexhibit a 0.5 mag dip near phase 0.75, but there is no such variabilityat longer wavelengths. Gas flow trajectories from the cusp of the K startoward the Be star provide a simple explanation for the photometric andspectroscopic behavior. We may have found a decreasing orbital period,but more data are necessary to confirm this result. We present severalmodels for AX Mon based on (1) new and archival visible photometry, (2)archival ultraviolet spectroscopy, (3) new and archival visiblespectroscopy, (4) new visible polarimetry, and (5) new radio photometry.Future observations, including optical interferometry, are proposed.
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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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Liste des étoiles Ap et Am dans les amas ouverts (édition révisée)
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Observations in regions of Cassiopeia, Gemini, and Monoceros with the Glazar space telescope
Observations at 1640 A of regions in Cassiopeia, Gemini, and Monocerosmade with the Glazar space telescope are presented; 7, 11, 13, and 35early-type stars brighter than about 9 mag were detected in the observedregions. The distribution of dust matter in the corresponding regions isstudied. It is determined that companions of HD 4442, 4797, and BD + 62deg 2225 are subdwarfs of sdB - sdO types; the hot companion of HD220102 may be of the type from B8 Ib-II to sdB. It is shown that HD 5233and 261490 are probably embedded in dense circumstellar envelopes.
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The formation of Be stars through close binary evolution
The possibility that Be stars are the remnants of case B mass transferin intermediate-mass close binaries is investigated. It is shown thatonly progenitors with mass ratios greater than a certain minimum valueq-min are capable of producing a Be star after the mass transfer. Thevalue of q-min lies between 0.3 and 0.5, depending on the evolutionparameters as well as on the observationally determined lower mass limitof Be/X-ray binaries. In more than 80 percent of the predicted systems,the evolved companion is an He star, particularly among the late-type Bstars; these systems may be detectable as XUV sources.
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Liste des étoiles Ap et Am dans les amas ouverts (Edition révisée)
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Catalog of AP and AM stars in open clusters
The previous results of Raab (1922), Markarian (1951), and Collinder(1931) have been used to catalog Ap and Am stars that are in the fieldof open clusters. Tabular data are presented for the clusterdesignation, the HD or HDE number, the right ascension (1900), thedeclination (1900), and the magnitude. Also listed are the spectraltypes and, for certain stars, the probability of cluster membership.
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Chemically peculiar stars in open clusters. I - The catalog
The largest existing compilation is presented of Ap and Am open clusterstars. The catalog contains information on 381 chemically peculiar (CP)stars of the upper main sequence in 79 open clusters. The catalog iscomposed of the following tables: (1) the main body, which lists CP (orsuspected CP) stars which are kinematical (or suspected kinematical)members of open clusters; (2) the list of CP (or suspected CP) starssometimes numbered among cluster members but which are actuallykinematical nonmembers; (3) the list of stars sometimes designated as'peculiar' but, in fact, probably not CP; (4) references for numberingsystems of cluster stars; (5) references for membership; and (6)references for spectral and/or peculiarity types.
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Statistical Investigation of Chemically Peculiar Stars - Part Four - Luminosity of Different Type Stars
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A catalog of ultraviolet interstellar extinction excesses for 1415 stars
Ultraviolet 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.
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The spectra and ages of blue stragglers
A mechanism similar to Wheeler's 'quasi-homogeneous evolution' and Finziand Wolf's proposal for blue stragglers is proposed as the origin of theblue stragglers in intermediate-age clusters. Blue stragglers are starswhose positions in color-magnitude diagrams of open and globularclusters are significantly above the turn-off points and in the regionof the (former) main sequence; they seem to represent a conflict withthe general conclusion that all stars in a cluster originated at aboutthe same time. It is concluded that there are at least two kinds of bluestragglers: (1) those stars of types about B3-A2 are primarily Ap starsand slow rotators, occur in the intermediate age clusters and remain inthe main sequence region probably through magnetic mixing; and (2) thestars of type O6-B2 frequently have emission lines, are rapid rotators,occur in the young cluster, and remain in the main sequence regionprobably by rotational mixing.
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Catalog of BV magnitudes and spectral classes of 6000 stars
The present catalog, compiled at the Abastumani Observatory, contains BVmagnitudes and spectral classes of about 6000 stars up to V(lim) = 13.0min five circular areas of 18 sq deg located near the salactic-equatorplane. The catalog is intended for star-statistics studies ofstar-formation regions.
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Stellar content of young open clusters. I - Blue stragglers. II - Be stars
The properties of the blue stragglers and Be stars found in openclusters younger than the Hyades are examined. Thirty-nine bluestragglers were detected at the left of the upper main sequence in thecolor-magnitude diagrams of 75 open clusters, with the frequency ofdetection noted to increase with cluster age. About half of thestragglers show peculiar abundance characteristics corresponding tospectral classes Am, Ap, Bp, Be and Of. The spectroscopic andphotometric behavior of the blue stragglers is, however, identical withthat of main sequence stars of the same type and peculiarity. It issuggested that the blue stragglers with peculiar spectroscopiccharacteristics may result from the evolution, perhapsquasi-homogeneous, of abnormal stars. Analysis of the absolutemagnitudes and dereddened colors calculated for 94 Be stars in 34 openclusters indicates the distribution to peak at spectral types B1-B2 andB7-B8, and in clusters with turn-up types at B1-B2. Cluster Be starsoccupy the whole main sequence band, and evolutionary states from nearlyunevolved to fully evolved. They may be classified according to theirposition on the color-magnitude diagram, with the distinctions betweenclasses also related to spectroscopic differences.
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The value of R in Monoceros
Recent photometric and spectroscopic observations are used inconjunction with other data for early-type stars in northern Monocerosin order to investigate the local value of R (the ratio of total toselective extinction). From a variable-extinction analysis, it isconcluded that a ratio of approximately 3.2 is appropriate for thegeneral interstellar extinction in this region and that there is noevidence here for the existence of local anomalies. The two majorassociations Mon OB 1 and Mon OB 2 are clearly delineated and are foundto exhibit properties typical of such young stellar groups. Derivedproperties for a few interesting stars are presented.
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Catalogue d'etoiles O et B.
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Galactic clusters as indicators of stellar evolution and galactic structure
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INHABITED SKY
