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A catalogue of eclipsing variables
A new catalogue of 6330 eclipsing variable stars is presented. Thecatalogue was developed from the General Catalogue of Variable Stars(GCVS) and its textual remarks by including recently publishedinformation about classification of 843 systems and making correspondingcorrections of GCVS data. The catalogue1 represents thelargest list of eclipsing binaries classified from observations.
| Hipparcos astrometry for 257 stars using Tycho-2 data
We present improved Hipparcos astrometry for 257 Hipparcos stars,resolved into 342 components. For 64 of the stars no astrometry wasobtained in the Hipparcos Catalogue, while for the remaining starsadditional components have been added by this solution or the positionshave been revised considerably. We have used the published Hipparcostransit data for the new solutions, together with results from thesecond reduction of the Tycho data for defining better initial values.Based on observations made with the ESA Hipparcos astrometry satellite.Table 3 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| 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.
| Spectroscopic observations of the interacting binary BY Crucis.
We present multi-wavelength spectroscopic data of the 106 day periodinteracting binary BY Crucis (Daems et al., 1997A&A...317..823D).The system consist of an early F-type supergiant that fills its Rochelobe and a more massive companion, hidden in a thick accretion disc. Inthe far-UV spectra (from 1200Å to 1950Å), strong emissionlines of highly ionised elements are observed, superposed on acontinuum. Both components of the UV flux originate from the accretiondisc around the companion. In the UV range from 1950Å to3150Å the radiation of the F-type mass donor is dominant. In thevisual and the red range we focused our interest on the Balmer lines(Halpha_, Hbeta_ and Hdelta_), He I5876Å, Na I 5890-5896Å, and the forbidden line [O I]6300Å. We also obtained spectra in various other regions, rangingfrom 3900Å to 6700Å. Evidence of mass transfer is observedin the He I-line, the Na I-lines, Hbeta_ and some Fe-lines.The Halpha_-line shows no variability, and its double peakedprofile implies that it is formed in a circumbinary disc or envelope.The [O I] line confirms the presence of matter around the binary system.By analysing the line profile variability of He I, we construct atentative image of the gas flow in the accretion disc around the unseencompanion. The Balmer lines are used to probe the outer, cooler gas,flowing through the outer Lagrangian point into a circumstellar disc orenvelope.
| Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
| The strongly constrained interacting binary BY Crucis.
We discuss spectroscopic and photometric observations (UV to IR) of BYCrucis, a new bright member of the interacting binaries of the WSerpentis class. The orbital period is 106.4days, and the mass functionamounts to 5.92Msun_. The primary is an early-F supergiantwhich fills its Roche lobe; the massive secondary is hidden inside athick accretion disk, which is probably the dominant light source in theultraviolet. The observed variations in the photometric lightcurves arecaused mainly by ellipsoidal variations. It is unlikely that an eclipseoccurs. A particularly interesting circumstance is that BY Cru is aprobable member of a visual multiple system which contains anotherevolved star. This circumstance enables us to estimate with someaccuracy the age of the interacting binary and the initial mass of theprimary. The history of this binary is then much more constrained thanfor the other W Serpentis stars. Also taking into account the fact thatthe binary has avoided Case C Roche lobe overflow, we determine upperand lower bounds for the initial and present masses of both components,and conclude that mass transfer has only been moderatelynon-conservative.
| 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.
| The calibration of Stromgren photometry for A, F and early G supergiants. III - The A and early F supergiants
This paper deals with the calibration of Stromgren photometry for the Aand early F supergiants. We derive a gravity parameter which can be usedto separate photometrically supergiants of different luminosity classes.It is used in conjunction to derive a simple calibration which gives theintrinsic color, of the supergiant. This calibration is tested andcompared with other reddening estimates for A and F supergiants in theliterature. Finally, we derive a semiempirical effective temperaturecalibration for the A and F supergiants.
| POST AGB candidates - Selection and IR properties
The properties of a group of stars is examined, that are selected on thebasis of the properties of two known post-AGB stars, HR 4049 and HD213985. It is shown that the stars from this sample that probably arepost-AGB stars all show IR excess. This excess can be due to hot (T =1000 K), cool (T = 300 K) or hot and cool dust. The stars showing thehot dust all have mass loss rates that are substantially larger than themass loss rates of the stars showing only cool dust. This indicates thatmass loss continues after the AGB at a substantial rate (about 10 to the-7th solar mass/yr). Selection criteria are given on the basis of whichpost-AGB stars can be selected from the literature.
| Long-Period Contact or Semidetached Systems - 5-CETI Cod: -30DEG5135 and HD104901B
Not Available
| The 68th Name-List of Variable Stars
Not Available
| A study of visual double stars with early type primaries. IV Astrophysical data
Astrophysical parameters (MK class, color excess, absolute magnitude,distance, effective temperature, mass, and age) are derived fromcalibrations of the uvby-beta indices for the members of 253 doublestars with O or B type primaries and faint secondaries. The photometricspectral classification is compared to the MK classes, and the agreementis very good. The derived data together with spectroscopic and JHKL dataare used for deciding which pairs are likely to be physical and whichare optical, and it is shown that 98 (34 percent) of the secondaries arelikely to be members of physical systems. For 90 percent of the physicalpairs the projected separation between the components is less than25,000 AU. A majority of the physical secondaries are late-type stars,and 50 percent of them are contracting towards the zero-agemain-sequence. Also presented are new uvby-beta data for 43 secondariesand a computer program for determining astrophysical parameters fromuvby-beta data.
| HD 104901B an F-Type Supergiant Eclipsing Binary
Not Available
| New UBVRI photometry for 900 supergiants
A description is presented of the results obtained in connection with asystematic program of supergiant photometry on the Johnson UBVRI system.During the eight years after the start of the program, almost 1000 starshave been observed, about 400 three or more times each. The originalselection of stars used the spectral type catalog of Jaschek et al.(1964) to choose supergiants. Since observations were possible from bothChile and Canada, no declination limits were imposed, and no particularselection criteria were imposed other than to eliminate carbon stars.These are so red as to require enormous extrapolations of thetransformation equations.
| A dust shell around the yellow supergiant CoD -61 deg 3326
Broad-band photometry from 1-4 microns and low-resolution spectrometry,in the 2-micron atmospheric window, of the F-type supergiant CoD -61 deg3326 equals Hz 747 are reported. The presence of an optically thin dustshell around this star is deduced and its properties are discussed withreference to the well-known yellow supergiant 89 Her. A similarpost-main-sequence evolutionary status is proposed for both stars.
| Near-infrared observations of trapezium-type multiple systems Catalogue of observations and a new determination of the reddening law
Results are presented from a large scale near-infrared survey of smallsky areas of the Milky Way containing trapezium-type multiple starsystems located within young galactic clusters, H II regions or darknebulosities. Photometric maps at wavelength 2.2 microns complemented bybroadband JHKL photometry of the majority of the sources detected and ofthe star members of the systems were obtained. A number of randomlychosen comparison regions along the galactic plane were also mapped andthe results were also used, with recent semi-empirical models, todetermine the number of field stars expected for the program surveys.Analyses of the infrared two-color diagrams provide determinations ofthe values of the color excess ratios E(J-H)/E(H-K), E(H-K)/E(K-L) andE(J-K)/E(K-L). The resulting reddening law is found to differsignificantly from that in the direction of the Ophiuchus and Taurusdark clouds and possibly towards the Galactic Center.
| On the connection of Trapezium type multiple systems with associations, galactic clusters, and emission nebulae
Not Available
| Catalog of multiple Trapezium type systems
Not Available
| 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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| קבוצת-כוכבים: | צלב דרומי |
| התרוממות ימנית: | 12h04m48.63s |
| סירוב: | -62°00'08.1" |
| גודל גלוי: | 7.785 |
| מרחק: | 980.392 פארסק |
| תנועה נכונה: | -5.4 |
| תנועה נכונה: | 4.7 |
| B-T magnitude: | 8.317 |
| V-T magnitude: | 7.829 |
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