CX CMa - An Early-Type Detached Eclipsing Binary
We present new B and V photometry of CX CMa and solve these light curvesusing the Wilson-Devinney program.
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New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
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A Search for High-Velocity Be Stars
We present an analysis of the kinematics of Be stars based uponHipparcos proper motions and published radial velocities. We findapproximately 23 of the 344 stars in our sample have peculiar spacemotions greater than 40 km s-1 and up to 102 kms-1. We argue that these high-velocity stars are the resultof either a supernova that disrupted a binary or ejection by closeencounters of binaries in young clusters. Be stars spun up by binarymass transfer will appear as high-velocity objects if there wassignificant mass loss during the supernova explosion of the initiallymore massive star, but the generally moderate peculiar velocities of BeX-ray binaries indicate that the progenitors lose most of their massprior to the supernova (in accordance with model predictions). Binaryformation models for Be stars predict that most systems bypass thesupernova stage (and do not receive runaway velocities) to createultimately Be+white dwarf binaries. The fraction of Be stars spun up bybinary mass transfer remains unknown, since the post-mass transfercompanions are difficult to detect.
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Statistical analysis of intrinsic polarization, IR excess and projected rotational velocity distributions of classical Be stars
We present the results of statistical analyses of a sample of 627 Bestars. The parameters of intrinsic polarization (p*),projected rotational velocity (v sin i), and near IR excesses have beeninvestigated. The values of p* have been estimated for a muchlarger and more representative sample of Be stars (~490 objects) thanpreviously. We have confirmed that most Be stars of early spectral typehave statistically larger values of polarization and IR excesses incomparison with the late spectral type stars. It is found that thedistributions of p* diverge considerably for the differentspectral subgroups. In contrast to late spectral types (B5-B9.5), thedistribution of p* for B0-B2 stars does not peak at the valuep*=0%. Statistically significant differences in the meanprojected rotational velocities (/line{vsin i}) are found for differentspectral subgroups of Be stars in the sense that late spectral typestars (V luminosity class) generally rotate faster than early types, inagreement with previously published results. This behaviour is, however,not obvious for the III-IV luminosity class stars. Nevertheless, thecalculated values of the ratio vt/vc of the truerotational velocity, vt, to the critical velocity forbreak-up, vc, is larger for late spectral type stars of allluminosity classes. Thus, late spectral type stars appear to rotatecloser to their break-up rotational velocity. The distribution of nearIR excesses for early spectral subgroups is bi-modal, the position ofthe second peak displaying a maximum value E(V-L)~ 1 . m 3for O-B1.5 stars, decreasing to E(V-L)~0. m8 for intermediatespectral types (B3-B5). It is shown that bi-modality disappears for latespectral types (B6-B9.5). No correlations were found betweenp* and near IR excesses and between E(V-L) and vsin i for thedifferent subgroups of Be stars. In contrast to near IR excesses, arelation between p* and far IR excesses at 12 mu m is clearlyseen. A clear relation between p* and vsin i (as well asbetween p* and /line{vsin i}/vc) is found by thefact that plots of these parameters are bounded by a ``triangular"distribution of p*: vsin i, with a decrease of p*towards very small and very large vsin i (and /line{vsini}/vc) values. The latter behaviour can be understood in thecontext of a larger oblateness of circumstellar disks for the stars witha rapid rotation. From the analysis of correlations between differentobservational parameters we conclude that circumstellar envelopes forthe majority of Be stars are optically thin disks with the range of thehalf-opening angle of 10degr
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On the Variability of O4-B5 Luminosity Class III-V Stars
We investigate the Hipparcos Satellite photometry of O4-B5 luminosityclass III-V stars. Some for which further study is desirable areidentified. These stars in general are more variable than cooler stars
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The distribution of bright OB stars in the Canis Major-Puppis-Vela region of the Milky Way
The picture of the young stellar groups in the Canis Major-Puppis-Vela(215 deg
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Sinusoidal variables from the Tycho Epoch Photometry Annex
The Tycho Epoch Photometry Annex A, a data base of photometry of morethan 34 000 bright stars, has been searched for periodic variablestars with approximately sinusoidal light curves. Advantage was taken ofspecial properties of the observing programme (photometry in twowavebands, availability of repeated measurements) to use simple butefficient variable selection criteria. Details of 70 strong candidatevariables are presented.
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Strömgren and Hβ photometry of O and B type stars in star-forming regions. I. Canis Major - Puppis - Vela
Strömgren and Hβ photometry of OB-stars generally brighterthan 9.5 mag in the Canis Major - Puppis - Vela region of Milky Way isreported. The observations are based on the Milky Way luminous-star (LS)identifications and are designed to create a complete, magnitude-limitedsample of LS for this field. We present new uvby photometry for 127 LSand Hβ photometry for 25 of them. These observations are part of anongoing effort to improve the completeness of the existing uvbybetadata-base for the bright OB-type stars in the Milky Way, with the aim toinvestigate the structure of selected star-forming regions. Based ondata from the Strömgren Automatic Telescope of the CopenhagenAstronomical Observatory, La Silla. Tables 3 and 4 are only available inelectronic form at the CDS via anonymous ftp to 130.79.128.5 or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
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UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
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A Radial Velocity Database for Stephenson-Sanduleak Southern Luminous Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....113..823R&db_key=AST
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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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A spectroscopic database for Stephenson-Sanduleak Southern Luminous Stars
A database of published spectral classifications for objects in theStepenson-Sanduleak Luminous Stars in the Southern Milky Way catalog hasbeen compiled from the literature. A total of 6182 classifications for2562 stars from 139 sources are incorporated.
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An Einstein Observatory SAO-based catalog of B-type stars
About 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.
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Spectral reclassification of some Be stars using Delta-Q method
The way in which the new defined value Delta-Q can play a role in thespectral reclassification of Be stars is shown by means of aninvestigation of 56 Be stars. A general survey carried out in order toobtain spectral subclasses or U, B, V values for these stars ispresented. The suggested Delta-Q method was found to be very helpful inchoosing the correct spectral subclass from among many subclassesassigned for the same star, and hence, the reclassification for thisstar.
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UBV photometry of OB+ stars in the southern Milky Way
One thousand two hundred and twenty six new observations are combinedwith previously published results of the author to yield an internalyconsistent set of magnitudes and colors on the international UBV systemfor 666 stars classified as OB+ in the Stephenson-Sanduleak OB starsurvey. The U - B, B - V diagram indicates that these stars consistprimarily of O-type stars and early B-type supergiants, reddened by upto E(B - V) = 2.1 mag.
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Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
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Physical parameters of pulsating variables with periods between one and three days. I - Photometry and metallicities
Based on a new set of observations in the Walraven VBLUW system,obtained at the European Southern Observatory, La Silla, Chile,Fe/H(VBLU) values of 57 pulsating variables, mostly with periods betweenone and three days,. are determined. The distribution of the metalabundances is shown to be essentially bimodal. All the variables withFe/H ratios of less than -0.4 were classified by Diethelm (1983) as RRdstars. They are identified as the galactic field counterpart of theCepheids in the same period range found in globular clusters.
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Far ultraviolet colors of B and Be stars
A far-UV color index, G, which is free of interstellar reddening effectsis applied to TD-1 satellite observations of B and Be stars listed inthe catalogs of Jamar et al. (1976) and Macau-Hercot et al. (1978). Theexpressions defining G(in terms of the wavelengths 146, 235, and 274 nm)and the S70 index of spectral type are set forth. Tables of mean andindividual-star G and S70 indices and plots of G versus S70, Delta-Gversus spectral type, Delta-G versus H-alpha and H-beta intensity, and Gversus V(sin i) are presented and discussed. The Be stars are classifiedas strong if they show strong Balmer emission, some Paschen and Fe IIemission, and IR excess; otherwise they are 'weak'. Weak Be stars arefound to have G similar to that of B stars, while G in strong Be starsis either much more negative or much less negative than in the B stars.No correlation is found between G and V(sin i) for either B or Be stars.
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New optical positions and proper motions of late type stars associated with SiO masers
The 33 cm astrograph of the Bordeaux Observatory has been used to derivewith respect to AGK3 reference stars, accurate positions of late typevariable stars variable stars associated with strong SiO maser emission.It is suggested that selected maser stars can be used to link theHIPPARCOS system and the VLBI extragalactic reference frame. The propermotions of the program (SiO) and reference stars are derived and, forthe program stars, are compared to the McCormick catalog of propermotions.
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UBV photometry for southern OB stars
New UBV photometry of 1227 OB stars in the southern Milky Way ispresented. For 1113 of these stars, MK spectral types have been reportedpreviously in a comprehensive survey to B = 10.0 mag.
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The ultraviolet reddening of Be stars
The UV extinction of several bright Be stars is examined in light ofSchild's (1978) demonstration of their intrinsic (B-V) color excess.Stars possessing this excess are found not to have the 0.22-micron bumpassociated with Bless and Savage's (1972) interstellar reddening law.The bright Be stars studied are HD 30076, HD 58011, HD 63462, and HD105435.
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Erratum - Distant Blue Stars in the Southern Milky-Way
Not Available
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The interstellar 2200 A band - A catalogue of equivalent widths
Not Available
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On the 4430 A interstellar band - A visual classification
A system of visual classification of the strength of the interstellarband 4430 A has been developed, based on spectra taken at spectralclassification dispersion. The intensity of the band was divided into 8main classes, defined by a group of selected standard stars. The systemwas applied to 1,111 southern OB stars contained in the catalog ofspectral types by Garrison, Hiltner, and Schild (1977). The mean errorin the classification was estimated to be plus or minus 1 class.Equivalent widths were measured for 100 stars; an excellent correlationwith the visual estimations was obtained. A calibration between thesetwo parameters is given.
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CO observations of a molecular cloud complex associated with the bright rim near VY Canis Majoris
Abstract image available at:http://adsabs.harvard.edu/abs/1978ApJ...219...95L
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MK spectral classifications for southern OB stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977ApJS...35..111G&db_key=AST
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Observations of southern emission-line stars
A catalog of 1929 stars showing H-alpha emission on photographic platesis presented which covers the entire southern sky south of declination-25 deg to a red limiting magnitude of about 11.0. The catalog providesprevious designations of known emission-line stars equatorial (1900) andgalactic coordinates, visual and photographic magnitudes, H-alphaemission parameters, spectral types, and notes on unusual spectralfeatures. The objects listed include 16 M stars, 25 S stars, 37 carbonstars, 20 symbiotic stars, 40 confirmed or suspected T Tauri stars, 16novae, 14 planetary nebulae, 11 P Cygni stars, 9 Bep stars, 87 confirmedor suspected Wolf-Rayet stars, and 26 'peculiar' stars. Two new Tassociations are discovered, one in Lupus and one in Chamaeleon. Objectswith variations in continuum or H-alpha intensity are noted, and thedistribution by spectral type is analyzed. It is found that the skydistribution of these emission-line stars shows significantconcentrations in the region of the small Sagittarius cloud and in theCarina region.
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Line strengths for southern OB stars. IV.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970MNRAS.148...79B&db_key=AST
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Line strengths for southern OB stars-II. Observations with moderate dispersion
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969MNRAS.144...31B&db_key=AST
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INHABITED SKY
