Contents
Images
Upload your image
DSS Images Other Images
Related articles
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.
| Statistical Constraints for Astrometric Binaries with Nonlinear Motion
Useful constraints on the orbits and mass ratios of astrometric binariesin the Hipparcos catalog are derived from the measured proper motiondifferences of Hipparcos and Tycho-2 (Δμ), accelerations ofproper motions (μ˙), and second derivatives of proper motions(μ̈). It is shown how, in some cases, statistical bounds can beestimated for the masses of the secondary components. Two catalogs ofastrometric binaries are generated, one of binaries with significantproper motion differences and the other of binaries with significantaccelerations of their proper motions. Mathematical relations betweenthe astrometric observables Δμ, μ˙, and μ̈ andthe orbital elements are derived in the appendices. We find a remarkabledifference between the distribution of spectral types of stars withlarge accelerations but small proper motion differences and that ofstars with large proper motion differences but insignificantaccelerations. The spectral type distribution for the former sample ofbinaries is the same as the general distribution of all stars in theHipparcos catalog, whereas the latter sample is clearly dominated bysolar-type stars, with an obvious dearth of blue stars. We point outthat the latter set includes mostly binaries with long periods (longerthan about 6 yr).
| Catalogue of Algol type binary stars
A catalogue of (411) Algol-type (semi-detached) binary stars ispresented in the form of five separate tables of information. Thecatalogue has developed from an earlier version by including more recentinformation and an improved layout. A sixth table lists (1872) candidateAlgols, about which fewer details are known at present. Some issuesrelating to the classification and interpretation of Algol-like binariesare also discussed.Catalogue 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/cgi-bin/qcat?J/A+A/417/263
| A catalog of rotational and radial velocities for evolved stars. II. Ib supergiant stars
Rotational velocity vsin i and mean radial velocity are presented for asample of 231 Ib supergiant stars covering the spectral region F, G andK. This work is the second part of the large survey carried out with theCORAVEL spectrometer to establish the behavior of the rotation for starsevolving off the main sequence (De Medeiros & Mayor 1999). Thesedata will add constraints to the study of the rotational behavior inevolved stars, as well as solid information concerning tidalinteractions in binary systems and on the link between rotation,chemical abundance and activity in stars of intermediate masses. Basedon observations collected at the Haute-Provence Observatory,Saint-Michel, France and at the European Southern Observatory, La Silla,Chile Table 1 is 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/395/97
| Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
| Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
| The Henize sample of S stars --- III. Uncovering the binary intruders
The properties of S stars are investigated thanks to a large observingprogram devoted to the well-defined Henize sample (205 S stars south ofδ = -25̂ and brighter than R = 10.5, covering allgalactic latitudes), in order to derive the respective properties of theintrinsic S stars (genuine thermally-pulsing AGB stars) and of theextrinsic S stars (post mass-transfer binaries). The stellar sample isfirst cleaned from a few stars misclassified as S thanks to UBV Genevaphotometry and low-resolution spectroscopy. These low-resolution spectraalso allow to successfully distinguish subclasses within the S starfamily. Dedicated Geneva photometry and high-resolution spectroscopyhave led to the discovery of two symbiotic S stars. The more stringentdifference between extrinsic and intrinsic stars is their technetiumcontent, but several other observational parameters are shown to beefficient to some extent in segregating intrinsic S stars from theirextrinsic masqueraders (UBV , JHKL and IRAS photometry, radial-velocitystandard deviation, shape of the CORAVEL cross-correlation dip,combination of band strength indices derived from low-resolutionspectra). Multivariate classification has been performed on the Henizedata sample in order to guarantee a classification as objective aspossible and handling at the same time a large number of parameters. Theresulting clusters separate efficiently extrinsic and intrinsic S stars,allowing to derive the respective properties of these two distinctstellar classes. The population difference between intrinsic andextrinsic S stars is for the first time clearly demonstrated, sinceintrinsic S stars are far more concentrated towards the galactic planethan extrinsic S stars (zint = 200 ∓ 100 pc andzext = 600 ∓ 100 pc), and are therefore believed tobelong to a younger, more massive population. The frequency of extrinsicand intrinsic S stars in the magnitude-limited Henize sample amounts to33% and 67%, respectively. In a volume-limited sample, this proportionis subject to large uncertainties mainly because of uncertainluminosities. There are probably as many as 40% extrinsic stars among Sstars in a volume-limited sample. Based on observations carried out atthe European Southern Observatory (ESO, La Silla, Chile) and at theSwiss 70 cm telescope (La Silla, Chile)
| Speckle Interferometry of New and Problem HIPPARCOS Binaries
The ESA Hipparcos satellite made measurements of over 12,000 doublestars and discovered 3406 new systems. In addition to these, 4706entries in the Hipparcos Catalogue correspond to double star solutionsthat did not provide the classical parameters of separation and positionangle (rho,theta) but were the so-called problem stars, flagged ``G,''``O,'' ``V,'' or ``X'' (field H59 of the main catalog). An additionalsubset of 6981 entries were treated as single objects but classified byHipparcos as ``suspected nonsingle'' (flag ``S'' in field H61), thusyielding a total of 11,687 ``problem stars.'' Of the many ground-basedtechniques for the study of double stars, probably the one with thegreatest potential for exploration of these new and problem Hipparcosbinaries is speckle interferometry. Results are presented from aninspection of 848 new and problem Hipparcos binaries, using botharchival and new speckle observations obtained with the USNO and CHARAspeckle cameras.
| Visual observations of the 1996 eclipse of BL Telescopii.
Not Available
| Visual observations of the 1994 eclipse of BL Telescopii.
Not Available
| Eclipsing binaries as IRAS sources.
In a systematic search we looked for coincidences in the positions ofeclipsing binaries and IRAS point sources as evidence of a physicalassociation. In a detailed discussion of the available optical andinfrared data combined with model calculations, we show that 50-75% ofthe coincidences between eclipsing binaries and IRAS sources are real.We discuss a subsample of 44 stars in some detail and surveyed thevicinity of them on POSS and SRC/ESO atlases for possible opticalcounterparts and present identification maps. In the cases of BS Sco andV 718 Sco the infrared radiation may come from an accretion disk.
| Colour excesses of F-G supergiants and Cepheids from Geneva photometry.
A reddening scale for F-G supergiants and Cepheids is presented.Supergiants with low reddenings or in clusters form the basis of thecalibration. In this sense, it is entirely empirical. The data have beenobtained in the Geneva photometric system. Comparisons with otherreddening scales show no disagreement. The only problem is with Fernie'sscale for Cepheids (1990), where a systematic trend exists. Its originis not clear. It is suggested to extend the number of supergiants withindependently obtained colour excesses in order to test the existence ofa possible luminosity dependence of the calibration. A period-colourrelation for Cepheids is deduced, on the basis of the present reddeningcorrections. It gives strong support for V473 Lyr being a secondovertone pulsator.
| Light and colour curves of the variable UU Herculis.
Not Available
| ROSAT Observations of Symbiotic Binaries and Related Objects
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.
| HD6474: an UU Her Spectrum Variable?
Not Available
| Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
| Post-main-sequence and POST red giant branch variables with pulsation periods less than one day
Post-main-sequence (mass 1 to 3 solar masses) and post-giant branch (0.5to 1 solar mass) pulsators are discussed on the basis of four color andH beta light curves published elsewhere. The post-main-sequencevariables, called ultrashort period cepheid (USPC) (delta Sct), pulsatein the fundamental and first harmonic modes of radial pulsation and, inmany cases, in nonradial modes. The variables for which photometryallows accurate, luminosity estimates and are known to pulsatesimultaneously in the fundamental and first harmonic or in thefundamental mode alone, define a PL relation (MV = -2.80 logP - 0.60, fundamental). It is notable that the slope of this relation isin the range of slopes found for classical cepheids. Accurate Vphotometry is lacking for many of the variables known as 'anomalouscepheids', but the available data divide them into low mass,pseudocepheids (BL Her and W Vir stars) and post-main-sequence USPC(delta Sct) variables. Four USPC in NGC 5053 and six in NGC 6466, forwhich accurate photometry is available, give remarkably consistentmoduli of 16.06 +/- 0.05 and 15.98 +/- 0.08 mag, respectively, for theclusters, in which they are blue stragglers similar to SX Phe inKapteyn's star group. The assumption that the four post-giant branchvariables, called VSPC (RR Lyr), S Ari, SU Dra, and ST Leo in Kapteyn'sstar group and RR Lyr in the Groombridge 1830 group, are physicalmembers of these groups and share their V-velocities, leads to acalibration of the photometry for the derivation of reddening,luminosity, and heavy element abundance of 45 field variables. Theresulting reddenings are consistent with values obtained by othermethods and the metallicities are consistent with the most accuratelyavailable spectroscopic determinations of delta S and of Ca II K. Theluminosities of the bulk of the variables confirm Sandage's (1993)relation between MV and (Fe/H). Four or five of the fieldvariables are probably binary, including BB Vir which Kinman &Carreta (1992) have independently noted as double. The PL relation forUSPC (delta Sct) variables intersects the horizontal branch (HB) near P= 0.3d and at least two field very short period cepheid (VSPC) (RR Lyr)star, FW Lup (0.484 d) and ST Pic (0.486 d) may be first overtonepulsators of the USPC (delta Sct) variety. A dozen field VSPC (RR Lyr)stars populate a (Fe/H), MV relation with the same slope asthe other stars but displaced 0.7 mag toward higher luminosities. Theonly cluster variable found to populate this diplaced relation is No. 9in 47 Tuc, although ST Vir, which may be a member of the Arcturus group,should also be considered. The elevated luminosities are unlikely to becaused by either evolution or errors in the photometric indices. Apossible source of these apparently young VSPC(RR Lyr) variables withhalo metallicity is in second (or third) generation globular clustersformed during an episodic collapse of the galaxy that produced metalpoor stars but in a dynamical situation that hastened the disruption ofthe clusters, currently formed, before the still older globularclusters, created under conditions that have kept them in a moredisruptive free environment.
| The pulsations of yellow semi-regular variables II. The F supergiant in the high-latitude binary BL Telescopii
Photoelectric observations of the F-type component of the high-latitudeeclipsing binary BL Telescopii outside eclipse were analysed. Twoperiods (92.5d and 64.8)d were found to be present in the light curve.They are identified as belonging to the fundamental mode and the firstovertone. It seems that BL Telescopii prefers overtone pulsation. Thepresence of the two periods and their ratio indicates that the high-massinterpretation of the variable could be valid. Together with UU Her andV487 Cas it belongs to the re-defined UU Herculis group of stars.
| Determination of two groups of high luminosity red variable stars.
Not Available
| A photometric and spectroscopic search for luminous high latitude stars
Formulas, derived by Arellano Ferro and Mendoza in Paper I (1993), tocalculate Mv, log g, and (Fe/H) were applied to a group of 73A, F, and G stars of high galactic latitude previously classified assupergiant stars. The only star that showed, from data on hand, to beluminous, slightly iron deficient, and out of the galactic plane was BLTelescopii. The remainder of the sample either present controversialresults or are definitively giant or dwarf stars misclassified assupergiants. Thus, if luminous, young stars indeed exist out of thegalactic plane, they are extremely rare.
| V487 Cassiopeiae (HD 6474): a UU Herculis variable in the galactic plane?
New photoelectric photometry of V487 Cassiopeiae (HD 6474) made between1984 and 1992 is presented. The star has a rather complicated lightvariation: at least two periods (P1 = 160.3 days andP2 = 99.6 days) are present in the light curve, one of thempossibly with variable amplitude. The period ratio(P2/P1 = 0.62) and the nature of the lightvariation (i.e. the simultaneous presence of two modes, the amplitudechange) are both very similar to that of UU Herculis. This similarityindicates that V487 Cassiopeiae is a UU Her-type variable though it isin the galactic plane. A distinction between the UU Her-type and 89Her-type variables is suggested.
| Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102...79S&db_key=AST
| The Double-Mode Semiregular Variable Uu-Herculis - 1990-1992 Photometry
Abstract image available at:http://adsabs.harvard.edu/abs/1993A&A...275..484Z
| Light variations of massive stars (Alpha Cygni variables). XII - The photometric history of the G8Ia(+) hypergiant V766 CEN (= HR 5171A) during the years 1953-1991 and its interpretation
VBLUW photometry of the G8 Ia(+) hypergiant V 766 Cen (= HR 5171A) madein the interval 1980-1991 is presented and discussed, together with UBVphotometry taken from the literature, which goes back in time until1953. The star shows a very strong reddening of about 0.65 m between1953 and 1981, a brightness oscillation with a quasi-period of 494 d, inthe interval 1973-1991, and a drop in brightness between 1973 and 1977.Whether the strong reddening is caused by an increasing circumstellardust density or by evolution to the red in the HR diagram is discussed.The radial velocity curve (1979-1981) appears to be in phase with thelight curve. This peculiar behavior is shared with the variable F-typesupergiant BL Tel(F). The radius variation amounts to about 8 percent.
| Catalogue of Population II A-F supergiants - UU Herculis and related stars
The catalogue of Population II A-F supergiants collects the availableinformation on 18 UU Herculis type and related stars. For each entry,the following information is presented: star name, equatorial andgalactic coordinates, spectral type, mean magnitude V, color index B-V,color excess E(B-V), metallicity Fe/H, absolute magnitude MV, effectivetemperature Te, and gravity log g. A list of six suspected UUHerculis-type stars is also presented.
| Visual observations of BL Telescopii.
Not Available
| The calibration of the Stromgren photometric system for A, F and early G supergiants. I - The observational data
An empirical calibration of the Stromgren uvby-beta photometric systemfor the A, F, and early G supergiants is being derived. This paperexplains the observational program and the photometric reductiontechniques used and presents a catalog of new Stromgren photometry forover 600 A, F, and G supergiants.
| Long-term photometry of variables at ESO. I - The first data catalogue (1982-1986)
This paper presents the catalog of photometric data in the Stromgrensystem obtained during the first four years (October 1982 - September1986) of the Long-Term Photometry of Variables (LTPV) program at ESO.The data are available in computer-readable form.
| 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.
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Τηλεσκόπιον |
| Right ascension: | 19h06m38.11s |
| Declination: | -51°25'03.2" |
| Apparent magnitude: | 7.214 |
| Distance: | 621.118 parsecs |
| Proper motion RA: | -6 |
| Proper motion Dec: | -0.7 |
| B-T magnitude: | 7.838 |
| V-T magnitude: | 7.266 |
Catalogs and designations:
|
