Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components.
A sample of 135 stars with composite spectra has been observed in thenear-UV spectral region with the Aurélie spectrograph at theObservatoire de Haute-Provence. Using the spectral classifications ofthe cool components previously determined with near infrared spectra, weobtained reliable spectral types of the hot components of the samplesystems. The hot components were isolated by the subtraction methodusing MK standards as surrogates of the cool components. We also derivedthe visual magnitude differences between the components usingWillstrop's normalized stellar flux ratios. We propose a photometricmodel for each of these systems on the basis of our spectroscopic dataand the Hipparcos data. We bring to light a discrepancy for the Gsupergiant primaries between the visual absolute magnitudes deduced fromHipparcos parallaxes and those tabulated by Schmidt-Kaler for the GIbstars: we propose a scale of Mv-values for these stars incomposite systems. By way of statistics, about 75% of the hot componentsare dwarf or subgiant stars, and 25% should be giants. The distributionin spectral types is as follows: 41% of B-type components, 57% of typeA, and 2% of type F; 68% of the hot components have a spectral type inthe range B7 to A2. The distribution of the ΔMv-valuesshows a maximum near 0.75 mag.
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Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
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Spectral classifications in the near infrared of stars with composite spectra. III. Study of a sample of 137 objects with the Aurelie spectrograph
We provide spectral classifications for a sample of 137 stars mentionedas having composite spectra. The classifications were carried out on 33Angstroms /mm spectra in the region 8370 - 8870 Angstroms. Of these 137objects, 115 correspond in the infrared to cool stars (G, K or M) ofluminosity classes III, II and I; for 22 stars, we find only hot spectraof types B, A, F or Am, so that they do not fulfil our definition ofcomposite spectra. We detect four new Am stars, and one Am star (HD70826) turns out to be a composite spectrum object. As in Paper II, thecool components of composite spectra show a strong concentration in thevicinity of G8III. Based upon observations carried out at Observatoirede Haute-Provence (OHP).
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Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample
We have obtained or retrieved IUE spectra for over 100 middle- andlate-type giant and supergiant stars whose spectra indicate the presenceof a hot component earlier than type F2. The hot companions areclassified accurately by temperature class from their far-UV spectra.The interstellar extinction of each system and the relative luminositiesof the components are derived from analysis of the UV and opticalfluxes, using a grid of UV intrinsic colors for hot dwarfs. We find thatthere is fair agreement in general between current UV spectralclassification and ground-based hot component types, in spite of thedifficulties of assigning the latter. There are a few cases in which thecool component optical classifications disagree considerably with thetemperature classes inferred from our analysis of UV and opticalphotometry. The extinction parameter agrees moderately well with otherdeterminations of B-V color excess. Many systems are worthy of furtherstudy especially to establish their spectroscopic orbits. Further workis planned to estimate luminosities of the cool components from the dataherein; in many cases, these luminosities' accuracies should becomparable to or exceed those of the Hipparcos parallaxes.
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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
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Accurate Positions for Radio Stars as Determined from CCD Observations in the Extragalactic Reference Frame.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.1679S&db_key=AST
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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.
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Some remarks on the origin of the abundance anomalies in HgMn stars.
Not Available
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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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Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
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ICCD speckle observations of binary stars. X - A further survey for duplicity among the bright stars
Speckle interferometric observations are reported for 1123 starsselected from the Yale Bright Star Catalogue (BSC) in a continuingeffort to detect new binaries among the bright stars. Thirty-twopreviously unresolved binaries have been detected, including companionsto Xi UMa and 15 S Mon. Measures of 107 previously resolved systems,many of which resulted from earlier speckle observations, are alsopresented. No evidence of duplicity within a specific (m, Delta-m, rho)window of detectability was found for 984 bright stars. Many of thesystems discovered earlier have shown significant orbital motions, andwe present preliminary orbital elements for six binaries. This efforthas resulted in the discovery of 75 new, bright binaries. We considersome aspects of the duplicity frequencies among the diverse spectral andluminosity classes represented in this sample. We anticipate that thecompletion of a speckle survey of the BSC would lead to the discovery ofat least 200 additional binary systems with angular separations mostlybelow 0.20 arcsec. Many of these will have periods of the order of onedecade and will be accessible to complementary radial velocity programsof enhanced precision.
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Circumstellar MGII Absorption in Ultraviolet Spectra of Hot Companions of Red Giants and the Meaning of the MGII Asymmetry Dividing Line
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&A...276..161H&db_key=AST
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An astrometric catalogue of radio stars
The first part is presented of a radio star catalog encompassing 186objects whose selection was guided by the priority criteria of theHipparchos Input Catalogue Consortium. Since these criteria are wellsuited to the need for linkage of ground-based optical systems to radioreference frames, this first selection is also considered a suitablebase for the catalog. Seventeen categories of stellar parameters arefurnished for each of the stars, including optical and radio positions,optical and radio parallax, radial velocity, type of variability, andoptical structure.
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Optical positions of radiostars. II
Precise optical positions, relative to either the Perth 70 or the AGK3Rcatalogs, have been obtained for 40 radiostars proposed to the Hipparcosobserving list. Precision levels between 0.18 and 0.29 arcsecs wereobtained.
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IUE and stars with composite spectra
The IUE contribution to the study of binary stars is reviewed. The valueof ultraviolet spectra in defining the parameters of hot companions indouble systems is emphasized, as this is important for understanding ofthe masses, luminosities, and evolutionary states of both the componentstars. Cataclysmic variables; precataclysmics; symbiotic stars;atmospheric eclipsing binaries; Algols; cool and hot binaries; heavymetal stars; noninteractors; and Cepheids are discussed.
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Miscellaneous spectroscopic notes
Results of slit-spectrograph observations are reported for approximately260 stars. The data presented range from recognition of many new Ap, Am,and other unusual stars to H-alpha observations of early-typesupergiants and Be stars. The material discussed was obtained over thepast 40 years at a number of U.S. observatories and at the DominionAstrophysical Observatory in Victoria, B.C.
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On the (B-V) colors of the bright stars
The possible causes of the dispersion of (B-V) colors of nearby stars inthe Bright Star Catalog are investigated. The distribution of (B-V)colors is presented for the entire range of spectral classes.Explanations for the dispersion in terms of a nonuniform distribution ofinterstellar absorbing material and a variability of metallicity areaddressed. A new statistical model for reddening by interstellar dustclouds is developed. It is concluded that extinction by nonuniforminterstellar matter is an important contribution to the reddening ofnearby stars, and that a part of the dispersion of (B-V) colors of Kand, possibly, M giants may be due to some unidentified variableproperty of those stars.
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Instrumental effects and the Stroemgren photometric system
The extent to which the use of different photometers can affect resultson stellar color indices was investigated by simultaneously observing asample of widely different stars with several uvby photometric systemsavailable at the ESO, La Silla, Chile. In one instance, the ESO 50-cmtelescope and the four-channel photometer at the Danish 50-cm telescopewere used simultaneously. The reductions were performed separately oneach data set, using a linear color transformation procedure. Theresults agree with theoretical investigations which showed thatsubstantial errors can arise from the nonconformity of passbands. It isemphasized that it is necessary to use separate color transformationsfor various stellar types and classes and for different interstellarreddenings.
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Ultraviolet survey for hot companions among nonvariable yellow supergiants
Twenty nonvariable yellow supergiants have been observed for the firsttime with the International Ultraviolet Explorer satellite, with the aimof discovering hot companions. Two newly discovered systems areannounced: HD 74395 (G2 I + B9.5 IV-V) and HD 193469 (later than G0 + B8IV-V). The Cepheid HD 9250 was also observed, but no hot companion wasfound. Some stars independently known to have a hot companion wereincluded in order to study the properties of the companions and tocompare with previous work. Atmospheric models were used to fit theoverall energy distribution of the binary system, allowing an estimateof Te, log g, and the spectral type of the companion. The magnitudedifferences, in the V band, between the yellow supergiants and theircompanions were calculated. The possibility of using this magnitudedifference and the spectral type determined for the hot companions toestimate M(v) for the yellow supergiants and the distance to the systemsis explored. Comparison of the binaries' positions in the H-R diagramwith theoretical evolutionary tracks suggests that the masses of theprimaries are contained between 5 and 9 solar masses and that, onaverage, they are about twice as massive as their hot companions.
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E. W. Fick Observatory stellar radial velocity measurements. I - 1976-1984
Stellar radial velocity observations made with the large vacuumhigh-dispersion photoelectric radial velocity spectrometer at FickObservatory are reported. This includes nearly 2000 late-type starsobserved during 585 nights. Gradual modifications to this instrumentover its first eight years of operation have reduced the observationalerror for high-quality dip observations to + or - 0.8 km/s.
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Ultraviolet and optical studies of binaries with luminous cool primaries and hot companions. III - RETICON radial velocities
Radial velocities for 72 stars, most of them known or suspected binarieswith F - K giant-supergiant primaries, are derived from Reticon spectrain the region 6005-6235 A at a scale of 7 km/s per diode.Cross-correlation of the spectra normally produces results accurate tobetter than 1.0 km/s. Eight new radial velocity variables are found (HR2786, R Pup, HR 3291, HR 4451, HD 114520, HR 5667, HR 7014, and Nu1Sgr). Improved orbits are determined for 15 known spectroscopicbinaries, and provisional orbits are obtained for seven newspectroscopic binaries.
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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.
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Nineteen new spectroscopic binaries and the rate of binary stars among F-M supergiants
Nineteen spectroscopic binaries (SBs) have been discovered in radialvelocity measurements made with the CORAVEL spectrophotometer on 181northern F-M supergiants. The rate of detected SBs among northern F-Msupergiants is 21 percent, without any dependence on spectral orluminosity class. The study of the binary F-M supergiants with knownorbital elements indicates that all the systems with a period smallerthan the critical value P(circ) have a nearly circular orbit. The valueof P(circ) depends on the luminosity class, being 400-600 d for class Iband 2000-7000 d for class Ia. This circularization of the orbits may bedue to the transfer of angular momentum during the phase of binary massexchange.
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Ultraviolet spectroscopy of F and G supergiants with IUE. II - The hot companions of HR 2786 and HR 2859
Hot companion stars in two binary systems are analyzed by means of IUElow-dispersion spectra. HR 2859B is found to be a B2 IV or V star, andanalysis of ultraviolet to near-infrared photometry indicates theprimary to be an early G star only one magnitude brighter in V with amagnitude of -4.0. A third star probably associated with this system wasclassified B9p Hg a probable visual absolute magnitude of about -1.6 isobtained for it. HR 2786 is now confirmed to have a hot secondary, forwhich a spectral class of B9-9.5 is obtained. With an assumed luminosityfor this component, the G2 Ib primary then has a magnitude of -3.8.
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Analysis of non-interacting binaries with luminous cool primaries
High dispersion long wave redundant (LWR) spectra are analyzed for thedifferential velocity between hot and cool components of heretoforesingle lined spectroscopic binaries with late type giant or supergiantprimaries. Cross correlation of a composite spectrum against early andlate type standard stars yields relative velocities with an accuracy of0.2 to 0.3 kms. When the orbit of the primay is known, the differentialmeasurement from IUE gives the mass ratio of the system. Low dispersionshort wave prime (SWP) and LWR flux spectra are used together withground-based photometry to disentangle the composite energydistributions of the binaries. Temperatures of both components, theirrelative luminosities, and the reddening of the system are obtained.Assuming the hot secondaries to be main sequence stars, their probableluminosities and masses may be obtained from their temperatures. Thenabsolute magnitudes and masses may be obtained for the evolved primarieswith more confidence than with existing techniques.
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Ultraviolet and optical studies of binaries with luminous cool primaries and hot companions. II - BVRI observations
Johnson system BVRI measurements are presented for 117 stars, most ofthem with no previous R and I photometry and many with no previous B andV. The prime objects for measurement are unresolved or nearly unresolvedbinaries containing a late-type giant or supergiant and an early-typecompanion. Other objects on the program include suspected binaries andother F-G giants and supergiants lacking at least R and I magnitudes.The variable F and G supergiants 1 Mon, 89 Her, HR 7308, HR 8157, HR8752, and rho-Cas and the eclipsing systems W Ser and ST Aqr wereobserved; HR 8752 showed significant dimming and cooling over 125 days.Several of Halliwell's (1979) candidates for nearby stars were measured.
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A survey of variable yellow supergiants in the southern Milky Way
Forty-three supergiants of spectral type F0-G8, including the RV Tauristar U Mon and the small-amplitude Cepheid HR 4768, have been monitoredin brightness for about a month. Three new variables are announced. HR6109 - a comparison star and a member of a spectroscopic binary with Pequals 40 days (Eggen 1973) - is suspected to be a Delta Scuti star. HR4912 shows a range of 0.32 magnitude in B; the period is between 44 and68 days. The Cepheid nature of HR 4912 cannot be established on thebasis of the data. HR 4110 - the central star of the galactic cluster IC2581 - shows a range in B of 0.07 magnitude and its most likely periodis about 59 days. Arguments are offered against the possible Cepheidinterpretation of HR 4110. The variability of HR 2910, HR 3026, and HD67458 is suspected. The star R Pup, which has been claimed anddisclaimed as a variable for a century, did not show significantvariation during the observing period.
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INHABITED SKY
